diff --git a/libfwupd/fwupd-client-sync.c b/libfwupd/fwupd-client-sync.c
index c263698f9..0342fe657 100644
--- a/libfwupd/fwupd-client-sync.c
+++ b/libfwupd/fwupd-client-sync.c
@@ -252,7 +252,7 @@ fwupd_client_get_releases_cb(GObject *source, GAsyncResult *res, gpointer user_d
 /**
  * fwupd_client_get_releases:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -306,7 +306,7 @@ fwupd_client_get_downgrades_cb(GObject *source, GAsyncResult *res, gpointer user
 /**
  * fwupd_client_get_downgrades:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -359,7 +359,7 @@ fwupd_client_get_upgrades_cb(GObject *source, GAsyncResult *res, gpointer user_d
 /**
  * fwupd_client_get_upgrades:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -534,7 +534,7 @@ fwupd_client_verify_cb(GObject *source, GAsyncResult *res, gpointer user_data)
 /**
  * fwupd_client_verify:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -583,7 +583,7 @@ fwupd_client_verify_update_cb(GObject *source, GAsyncResult *res, gpointer user_
 /**
  * fwupd_client_verify_update:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -636,7 +636,7 @@ fwupd_client_unlock_cb(GObject *source, GAsyncResult *res, gpointer user_data)
 /**
  * fwupd_client_unlock:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -792,7 +792,7 @@ fwupd_client_clear_results_cb(GObject *source, GAsyncResult *res, gpointer user_
 /**
  * fwupd_client_clear_results:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -845,7 +845,7 @@ fwupd_client_get_results_cb(GObject *source, GAsyncResult *res, gpointer user_da
 /**
  * fwupd_client_get_results:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -1110,7 +1110,7 @@ fwupd_client_install_fd_cb(GObject *source, GAsyncResult *res, gpointer user_dat
 /**
  * fwupd_client_install:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @filename: the filename to install
  * @install_flags: install flags, e.g. %FWUPD_INSTALL_FLAG_ALLOW_REINSTALL
  * @cancellable: (nullable): optional #GCancellable
@@ -1185,7 +1185,7 @@ fwupd_client_install_bytes_cb(GObject *source, GAsyncResult *res, gpointer user_
 /**
  * fwupd_client_install_bytes:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @bytes: cabinet archive
  * @install_flags: install flags, e.g. %FWUPD_INSTALL_FLAG_ALLOW_REINSTALL
  * @cancellable: (nullable): optional #GCancellable
@@ -1654,9 +1654,9 @@ fwupd_client_modify_device_cb(GObject *source, GAsyncResult *res, gpointer user_
 /**
  * fwupd_client_modify_device:
  * @self: a #FwupdClient
- * @device_id: the device ID
- * @key: the key, e.g. `Flags`
- * @value: the key, e.g. `reported`
+ * @device_id: (not nullable): the device ID
+ * @key: (not nullable): the key, e.g. `Flags`
+ * @value: (not nullable): the key, e.g. `reported`
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -1873,7 +1873,7 @@ fwupd_client_set_approved_firmware_cb(GObject *source, GAsyncResult *res, gpoint
 /**
  * fwupd_client_set_approved_firmware:
  * @self: a #FwupdClient
- * @checksums: Array of checksums
+ * @checksums: (not nullable): Array of checksums
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -2095,7 +2095,7 @@ fwupd_client_self_sign_cb(GObject *source, GAsyncResult *res, gpointer user_data
 /**
  * fwupd_client_self_sign:
  * @self: a #FwupdClient
- * @value: a string to sign, typically a JSON blob
+ * @value: (not nullable): a string to sign, typically a JSON blob
  * @flags: signing flags, e.g. %FWUPD_SELF_SIGN_FLAG_ADD_TIMESTAMP
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
@@ -2152,7 +2152,7 @@ fwupd_client_download_bytes_cb(GObject *source, GAsyncResult *res, gpointer user
 /**
  * fwupd_client_download_bytes:
  * @self: a #FwupdClient
- * @url: the remote URL
+ * @url: (not nullable): the remote URL
  * @flags: download flags, e.g. %FWUPD_CLIENT_DOWNLOAD_FLAG_NONE
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
@@ -2202,8 +2202,8 @@ fwupd_client_download_bytes(FwupdClient *self,
 /**
  * fwupd_client_download_file:
  * @self: a #FwupdClient
- * @url: the remote URL
- * @file: a file
+ * @url: (not nullable): the remote URL
+ * @file: (not nullable): a file
  * @flags: download flags, e.g. %FWUPD_CLIENT_DOWNLOAD_FLAG_NONE
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
@@ -2261,8 +2261,8 @@ fwupd_client_upload_bytes_cb(GObject *source, GAsyncResult *res, gpointer user_d
 /**
  * fwupd_client_upload_bytes:
  * @self: a #FwupdClient
- * @url: the remote URL
- * @payload: payload string
+ * @url: (not nullable): the remote URL
+ * @payload: (not nullable): payload string
  * @signature: (nullable): signature string
  * @flags: download flags, e.g. %FWUPD_CLIENT_DOWNLOAD_FLAG_NONE
  * @cancellable: (nullable): optional #GCancellable
diff --git a/libfwupd/fwupd-client.c b/libfwupd/fwupd-client.c
index ea7dff2ac..afd5619e5 100644
--- a/libfwupd/fwupd-client.c
+++ b/libfwupd/fwupd-client.c
@@ -1385,7 +1385,7 @@ fwupd_client_get_device_by_id_cb(GObject *source, GAsyncResult *res, gpointer us
 /**
  * fwupd_client_get_device_by_id_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -1564,7 +1564,7 @@ fwupd_client_get_releases_cb(GObject *source, GAsyncResult *res, gpointer user_d
 /**
  * fwupd_client_get_releases_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -1647,7 +1647,7 @@ fwupd_client_get_downgrades_cb(GObject *source, GAsyncResult *res, gpointer user
 /**
  * fwupd_client_get_downgrades_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -1730,7 +1730,7 @@ fwupd_client_get_upgrades_cb(GObject *source, GAsyncResult *res, gpointer user_d
 /**
  * fwupd_client_get_upgrades_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -1972,7 +1972,7 @@ fwupd_client_verify_cb(GObject *source, GAsyncResult *res, gpointer user_data)
 /**
  * fwupd_client_verify_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -2050,7 +2050,7 @@ fwupd_client_verify_update_cb(GObject *source, GAsyncResult *res, gpointer user_
 /**
  * fwupd_client_verify_update_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -2128,7 +2128,7 @@ fwupd_client_unlock_cb(GObject *source, GAsyncResult *res, gpointer user_data)
 /**
  * fwupd_client_unlock_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -2286,7 +2286,7 @@ fwupd_client_get_results_cb(GObject *source, GAsyncResult *res, gpointer user_da
 /**
  * fwupd_client_get_results_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -2456,7 +2456,7 @@ fwupd_client_install_stream_async(FwupdClient *self,
 /**
  * fwupd_client_install_bytes_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @bytes: cabinet archive
  * @install_flags: install flags, e.g. %FWUPD_INSTALL_FLAG_ALLOW_REINSTALL
  * @cancellable: (nullable): optional #GCancellable
@@ -2539,7 +2539,7 @@ fwupd_client_install_bytes_finish(FwupdClient *self, GAsyncResult *res, GError *
 /**
  * fwupd_client_install_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
+ * @device_id: (not nullable): the device ID
  * @filename: the filename to install
  * @install_flags: install flags, e.g. %FWUPD_INSTALL_FLAG_ALLOW_REINSTALL
  * @cancellable: (nullable): optional #GCancellable
@@ -4295,9 +4295,9 @@ fwupd_client_modify_device_cb(GObject *source, GAsyncResult *res, gpointer user_
 /**
  * fwupd_client_modify_device_async:
  * @self: a #FwupdClient
- * @device_id: the device ID
- * @key: the key, e.g. `Flags`
- * @value: the value, e.g. `reported`
+ * @device_id: (not nullable): the device ID
+ * @key: (not nullable): the key, e.g. `Flags`
+ * @value: (not nullable): the value, e.g. `reported`
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -4402,7 +4402,7 @@ fwupd_client_get_remote_by_id_cb(GObject *source, GAsyncResult *res, gpointer us
 /**
  * fwupd_client_get_remote_by_id_async:
  * @self: a #FwupdClient
- * @remote_id: the remote ID, e.g. `lvfs-testing`
+ * @remote_id: (not nullable): the remote ID, e.g. `lvfs-testing`
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
  * @callback_data: the data to pass to @callback
@@ -4505,8 +4505,8 @@ fwupd_client_get_user_agent(FwupdClient *self)
 /**
  * fwupd_client_set_user_agent_for_package:
  * @self: a #FwupdClient
- * @package_name: client program name, e.g. `gnome-software`
- * @package_version: client program version, e.g. `3.28.1`
+ * @package_name: (not nullable): client program name, e.g. `gnome-software`
+ * @package_version: (not nullable): client program version, e.g. `3.28.1`
  *
  * Builds a user-agent to use for the download.
  *
@@ -4748,7 +4748,7 @@ fwupd_client_download_bytes2_async(FwupdClient *self,
 /**
  * fwupd_client_download_bytes_async:
  * @self: a #FwupdClient
- * @url: the remote URL
+ * @url: (not nullable): the remote URL
  * @flags: download flags, e.g. %FWUPD_CLIENT_DOWNLOAD_FLAG_NONE
  * @cancellable: (nullable): optional #GCancellable
  * @callback: the function to run on completion
@@ -4857,8 +4857,8 @@ fwupd_client_upload_bytes_thread_cb(GTask *task,
 /**
  * fwupd_client_upload_bytes_async:
  * @self: a #FwupdClient
- * @url: the remote URL
- * @payload: payload string
+ * @url: (not nullable): the remote URL
+ * @payload: (not nullable): payload string
  * @signature: (nullable): signature string
  * @flags: download flags, e.g. %FWUPD_CLIENT_DOWNLOAD_FLAG_NONE
  * @cancellable: (nullable): optional #GCancellable
@@ -4965,7 +4965,7 @@ fwupd_client_upload_bytes_finish(FwupdClient *self, GAsyncResult *res, GError **
 /**
  * fwupd_client_add_hint:
  * @self: a #FwupdClient
- * @key: the key, e.g. `locale`
+ * @key: (not nullable): the key, e.g. `locale`
  * @value: (nullable): the value @key should be set
  *
  * Sets optional hints from the client that may affect the list of devices.
diff --git a/libfwupd/fwupd-common.c b/libfwupd/fwupd-common.c
index eb47de378..4e0d28ce9 100644
--- a/libfwupd/fwupd-common.c
+++ b/libfwupd/fwupd-common.c
@@ -35,7 +35,7 @@
 
 /**
  * fwupd_checksum_guess_kind:
- * @checksum: a checksum
+ * @checksum: (nullable): a checksum
  *
  * Guesses the checksum kind based on the length of the hash.
  *
@@ -77,7 +77,7 @@ fwupd_checksum_type_to_string_display(GChecksumType checksum_type)
 
 /**
  * fwupd_checksum_format_for_display:
- * @checksum: a checksum
+ * @checksum: (nullable): a checksum
  *
  * Formats a checksum for display.
  *
@@ -282,8 +282,8 @@ fwupd_build_user_agent_system(void)
 
 /**
  * fwupd_build_user_agent:
- * @package_name: client program name, e.g. `gnome-software`
- * @package_version: client program version, e.g. `3.28.1`
+ * @package_name: (not nullable): client program name, e.g. `gnome-software`
+ * @package_version: (not nullable): client program version, e.g. `3.28.1`
  *
  * Builds a user-agent to use for the download.
  *
@@ -716,8 +716,8 @@ g_ascii_string_to_unsigned(const gchar *str,
 
 /**
  * fwupd_guid_from_string:
- * @guidstr: (nullable): a GUID, e.g. `00112233-4455-6677-8899-aabbccddeeff`
- * @guid: a #fwupd_guid_t, or NULL to just check the GUID
+ * @guidstr: (not nullable): a GUID, e.g. `00112233-4455-6677-8899-aabbccddeeff`
+ * @guid: (nullable): a #fwupd_guid_t, or NULL to just check the GUID
  * @flags: GUID flags, e.g. %FWUPD_GUID_FLAG_MIXED_ENDIAN
  * @error: (nullable): optional return location for an error
  *
diff --git a/libfwupd/fwupd-device.c b/libfwupd/fwupd-device.c
index 3ecce500f..dc40b2383 100644
--- a/libfwupd/fwupd-device.c
+++ b/libfwupd/fwupd-device.c
@@ -108,7 +108,7 @@ fwupd_device_get_checksums(FwupdDevice *self)
 /**
  * fwupd_device_add_checksum:
  * @self: a #FwupdDevice
- * @checksum: the device checksum
+ * @checksum: (not nullable): the device checksum
  *
  * Adds a device checksum.
  *
@@ -551,7 +551,7 @@ fwupd_device_get_guids(FwupdDevice *self)
 /**
  * fwupd_device_has_guid:
  * @self: a #FwupdDevice
- * @guid: the GUID, e.g. `2082b5e0-7a64-478a-b1b2-e3404fab6dad`
+ * @guid: (not nullable): the GUID, e.g. `2082b5e0-7a64-478a-b1b2-e3404fab6dad`
  *
  * Finds out if the device has this specific GUID.
  *
@@ -636,7 +636,7 @@ fwupd_device_get_instance_ids(FwupdDevice *self)
 /**
  * fwupd_device_has_instance_id:
  * @self: a #FwupdDevice
- * @instance_id: the instance ID, e.g. `PCI\VEN_10EC&DEV_525A`
+ * @instance_id: (not nullable): the instance ID, e.g. `PCI\VEN_10EC&DEV_525A`
  *
  * Finds out if the device has this specific instance ID.
  *
@@ -663,7 +663,7 @@ fwupd_device_has_instance_id(FwupdDevice *self, const gchar *instance_id)
 /**
  * fwupd_device_add_instance_id:
  * @self: a #FwupdDevice
- * @instance_id: the instance ID, e.g. `PCI\VEN_10EC&DEV_525A`
+ * @instance_id: (not nullable): the instance ID, e.g. `PCI\VEN_10EC&DEV_525A`
  *
  * Adds the instance ID if it does not already exist.
  *
@@ -727,7 +727,7 @@ fwupd_device_has_icon(FwupdDevice *self, const gchar *icon)
 /**
  * fwupd_device_add_icon:
  * @self: a #FwupdDevice
- * @icon: the icon name, e.g. `input-mouse` or `/usr/share/icons/foo.png`
+ * @icon: (not nullable): the icon name, e.g. `input-mouse` or `/usr/share/icons/foo.png`
  *
  * Adds the icon name if it does not already exist.
  *
@@ -849,7 +849,7 @@ fwupd_device_get_vendor_id(FwupdDevice *self)
 /**
  * fwupd_device_set_vendor_id:
  * @self: a #FwupdDevice
- * @vendor_id: the vendor ID, e.g. 'USB:0x1234' or 'USB:0x1234|PCI:0x5678'
+ * @vendor_id: (not nullable): the vendor ID, e.g. 'USB:0x1234' or 'USB:0x1234|PCI:0x5678'
  *
  * Sets the device vendor ID.
  *
@@ -892,7 +892,7 @@ fwupd_device_get_vendor_ids(FwupdDevice *self)
 /**
  * fwupd_device_has_vendor_id:
  * @self: a #FwupdDevice
- * @vendor_id: the vendor ID, e.g. 'USB:0x1234'
+ * @vendor_id: (not nullable): the vendor ID, e.g. 'USB:0x1234'
  *
  * Finds out if the device has this specific vendor ID.
  *
@@ -919,7 +919,7 @@ fwupd_device_has_vendor_id(FwupdDevice *self, const gchar *vendor_id)
 /**
  * fwupd_device_add_vendor_id:
  * @self: a #FwupdDevice
- * @vendor_id: the ID, e.g. 'USB:0x1234'
+ * @vendor_id: (not nullable): the ID, e.g. 'USB:0x1234'
  *
  * Adds a device vendor ID.
  *
@@ -1316,7 +1316,7 @@ fwupd_device_get_protocol(FwupdDevice *self)
 /**
  * fwupd_device_set_protocol:
  * @self: a #FwupdDevice
- * @protocol: the protocol name, e.g. `com.hughski.colorhug`
+ * @protocol: (not nullable): the protocol name, e.g. `com.hughski.colorhug`
  *
  * Sets the protocol name that is used to update the device.
  *
@@ -1359,7 +1359,7 @@ fwupd_device_get_protocols(FwupdDevice *self)
 /**
  * fwupd_device_has_protocol:
  * @self: a #FwupdDevice
- * @protocol: the protocol name, e.g. `com.hughski.colorhug`
+ * @protocol: (not nullable): the protocol name, e.g. `com.hughski.colorhug`
  *
  * Finds out if the device has this specific protocol name.
  *
@@ -1386,7 +1386,7 @@ fwupd_device_has_protocol(FwupdDevice *self, const gchar *protocol)
 /**
  * fwupd_device_add_protocol:
  * @self: a #FwupdDevice
- * @protocol: the protocol name, e.g. `com.hughski.colorhug`
+ * @protocol: (not nullable): the protocol name, e.g. `com.hughski.colorhug`
  *
  * Adds a device protocol name.
  *
@@ -2507,7 +2507,7 @@ fwupd_device_get_releases(FwupdDevice *self)
 /**
  * fwupd_device_add_release:
  * @self: a #FwupdDevice
- * @release: a release
+ * @release: (not nullable): a release
  *
  * Adds a release for this device.
  *
@@ -2570,7 +2570,7 @@ fwupd_pad_kv_ups(GString *str, const gchar *key, FwupdUpdateState value)
 /**
  * fwupd_device_to_json:
  * @self: a #FwupdDevice
- * @builder: a JSON builder
+ * @builder: (not nullable): a JSON builder
  *
  * Adds a fwupd device to a JSON builder
  *
@@ -2966,6 +2966,13 @@ fwupd_device_class_init(FwupdDeviceClass *klass)
 	object_class->get_property = fwupd_device_get_property;
 	object_class->set_property = fwupd_device_set_property;
 
+	/**
+	 * FwupdDevice:version-format:
+	 *
+	 * The version format of the device.
+	 *
+	 * Since: 1.2.9
+	 */
 	pspec = g_param_spec_uint("version-format",
 				  NULL,
 				  NULL,
@@ -2975,6 +2982,13 @@ fwupd_device_class_init(FwupdDeviceClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_VERSION_FORMAT, pspec);
 
+	/**
+	 * FwupdDevice:flags:
+	 *
+	 * The device flags.
+	 *
+	 * Since: 0.9.3
+	 */
 	pspec = g_param_spec_uint64("flags",
 				    NULL,
 				    NULL,
@@ -2984,6 +2998,14 @@ fwupd_device_class_init(FwupdDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_FLAGS, pspec);
 
+	/**
+	 * FwupdDevice:protocol:
+	 *
+	 * The device protocol.
+	 *
+	 * Since: 1.3.6
+	 * Deprecated: 1.5.8
+	 */
 	pspec = g_param_spec_string("protocol",
 				    NULL,
 				    NULL,
@@ -2991,6 +3013,13 @@ fwupd_device_class_init(FwupdDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_PROTOCOL, pspec);
 
+	/**
+	 * FwupdDevice:status:
+	 *
+	 * The current device status.
+	 *
+	 * Since: 1.4.0
+	 */
 	pspec = g_param_spec_uint("status",
 				  NULL,
 				  NULL,
@@ -3000,6 +3029,13 @@ fwupd_device_class_init(FwupdDeviceClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_STATUS, pspec);
 
+	/**
+	 * FwupdDevice:parent:
+	 *
+	 * The device parent.
+	 *
+	 * Since: 1.0.8
+	 */
 	pspec = g_param_spec_object("parent",
 				    NULL,
 				    NULL,
@@ -3007,6 +3043,13 @@ fwupd_device_class_init(FwupdDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_PARENT, pspec);
 
+	/**
+	 * FwupdDevice:update-state:
+	 *
+	 * The device update state.
+	 *
+	 * Since: 0.9.8
+	 */
 	pspec = g_param_spec_uint("update-state",
 				  NULL,
 				  NULL,
@@ -3016,6 +3059,13 @@ fwupd_device_class_init(FwupdDeviceClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_UPDATE_STATE, pspec);
 
+	/**
+	 * FwupdDevice:update-message:
+	 *
+	 * The device update message.
+	 *
+	 * Since: 1.2.4
+	 */
 	pspec = g_param_spec_string("update-message",
 				    NULL,
 				    NULL,
@@ -3023,6 +3073,13 @@ fwupd_device_class_init(FwupdDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_UPDATE_MESSAGE, pspec);
 
+	/**
+	 * FwupdDevice:update-error:
+	 *
+	 * The device update error.
+	 *
+	 * Since: 0.9.8
+	 */
 	pspec = g_param_spec_string("update-error",
 				    NULL,
 				    NULL,
@@ -3030,6 +3087,13 @@ fwupd_device_class_init(FwupdDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_UPDATE_ERROR, pspec);
 
+	/**
+	 * FwupdDevice:update-image:
+	 *
+	 * The update image for the device.
+	 *
+	 * Since: 1.4.5
+	 */
 	pspec = g_param_spec_string("update-image",
 				    NULL,
 				    NULL,
@@ -3108,7 +3172,7 @@ fwupd_device_set_from_variant_iter(FwupdDevice *self, GVariantIter *iter)
 
 /**
  * fwupd_device_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates a new device using serialized data.
  *
@@ -3178,7 +3242,7 @@ fwupd_device_array_ensure_parents(GPtrArray *devices)
 
 /**
  * fwupd_device_array_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates an array of new devices using serialized data.
  *
diff --git a/libfwupd/fwupd-enums.c b/libfwupd/fwupd-enums.c
index 529f1a3d3..b0cab6289 100644
--- a/libfwupd/fwupd-enums.c
+++ b/libfwupd/fwupd-enums.c
@@ -54,7 +54,7 @@ fwupd_status_to_string(FwupdStatus status)
 
 /**
  * fwupd_status_from_string:
- * @status: a string, e.g. `decompressing`
+ * @status: (nullable): a string, e.g. `decompressing`
  *
  * Converts a string to an enumerated status.
  *
@@ -208,7 +208,7 @@ fwupd_device_flag_to_string(FwupdDeviceFlags device_flag)
 
 /**
  * fwupd_device_flag_from_string:
- * @device_flag: a string, e.g. `require-ac`
+ * @device_flag: (nullable): a string, e.g. `require-ac`
  *
  * Converts a string to a enumerated device flag.
  *
@@ -363,7 +363,7 @@ fwupd_plugin_flag_to_string(FwupdPluginFlags plugin_flag)
 
 /**
  * fwupd_plugin_flag_from_string:
- * @plugin_flag: a string, e.g. `require-ac`
+ * @plugin_flag: (nullable): a string, e.g. `require-ac`
  *
  * Converts a string to an enumerated plugin flag.
  *
@@ -435,7 +435,7 @@ fwupd_update_state_to_string(FwupdUpdateState update_state)
 
 /**
  * fwupd_update_state_from_string:
- * @update_state: a string, e.g. `pending`
+ * @update_state: (nullable): a string, e.g. `pending`
  *
  * Converts a string to a enumerated update state.
  *
@@ -485,7 +485,7 @@ fwupd_trust_flag_to_string(FwupdTrustFlags trust_flag)
 
 /**
  * fwupd_trust_flag_from_string:
- * @trust_flag: a string, e.g. `payload`
+ * @trust_flag: (nullable): a string, e.g. `payload`
  *
  * Converts a string to a enumerated trust flag.
  *
@@ -537,7 +537,7 @@ fwupd_feature_flag_to_string(FwupdFeatureFlags feature_flag)
 
 /**
  * fwupd_feature_flag_from_string:
- * @feature_flag: a string, e.g. `detach-action`
+ * @feature_flag: (nullable): a string, e.g. `detach-action`
  *
  * Converts a string to a enumerated feature flag.
  *
@@ -567,7 +567,7 @@ fwupd_feature_flag_from_string(const gchar *feature_flag)
 
 /**
  * fwupd_keyring_kind_from_string:
- * @keyring_kind: a string, e.g. `gpg`
+ * @keyring_kind: (nullable): a string, e.g. `gpg`
  *
  * Converts an printable string to an enumerated keyring kind.
  *
@@ -647,7 +647,7 @@ fwupd_release_flag_to_string(FwupdReleaseFlags release_flag)
 
 /**
  * fwupd_release_flag_from_string:
- * @release_flag: a string, e.g. `trusted-payload`
+ * @release_flag: (nullable): a string, e.g. `trusted-payload`
  *
  * Converts a string to an enumerated release flag.
  *
@@ -701,7 +701,7 @@ fwupd_release_urgency_to_string(FwupdReleaseUrgency release_urgency)
 
 /**
  * fwupd_release_urgency_from_string:
- * @release_urgency: a string, e.g. `low`
+ * @release_urgency: (nullable): a string, e.g. `low`
  *
  * Converts a string to an enumerated release urgency value.
  *
@@ -725,7 +725,7 @@ fwupd_release_urgency_from_string(const gchar *release_urgency)
 
 /**
  * fwupd_version_format_from_string:
- * @str: a string, e.g. `quad`
+ * @str: (nullable): a string, e.g. `quad`
  *
  * Converts text to a display version type.
  *
diff --git a/libfwupd/fwupd-error.c b/libfwupd/fwupd-error.c
index 73018134e..9f98b939e 100644
--- a/libfwupd/fwupd-error.c
+++ b/libfwupd/fwupd-error.c
@@ -64,7 +64,7 @@ fwupd_error_to_string(FwupdError error)
 
 /**
  * fwupd_error_from_string:
- * @error: a string, e.g. `org.freedesktop.fwupd.VersionNewer`
+ * @error: (nullable): a string, e.g. `org.freedesktop.fwupd.VersionNewer`
  *
  * Converts a string to an enumerated error.
  *
diff --git a/libfwupd/fwupd-plugin.c b/libfwupd/fwupd-plugin.c
index 057099b57..f92a2738e 100644
--- a/libfwupd/fwupd-plugin.c
+++ b/libfwupd/fwupd-plugin.c
@@ -355,10 +355,24 @@ fwupd_plugin_class_init(FwupdPluginClass *klass)
 	object_class->get_property = fwupd_plugin_get_property;
 	object_class->set_property = fwupd_plugin_set_property;
 
+	/**
+	 * FwupdPlugin:name:
+	 *
+	 * The plugin name.
+	 *
+	 * Since: 1.5.0
+	 */
 	pspec =
 	    g_param_spec_string("name", NULL, NULL, NULL, G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_NAME, pspec);
 
+	/**
+	 * FwupdPlugin:flags:
+	 *
+	 * The plugin flags.
+	 *
+	 * Since: 1.5.0
+	 */
 	pspec = g_param_spec_uint64("flags",
 				    NULL,
 				    NULL,
@@ -396,7 +410,7 @@ fwupd_plugin_set_from_variant_iter(FwupdPlugin *self, GVariantIter *iter)
 
 /**
  * fwupd_plugin_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates a new plugin using serialized data.
  *
@@ -429,7 +443,7 @@ fwupd_plugin_from_variant(GVariant *value)
 
 /**
  * fwupd_plugin_array_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates an array of new plugins using serialized data.
  *
diff --git a/libfwupd/fwupd-release.c b/libfwupd/fwupd-release.c
index 28fe255ec..71966cff1 100644
--- a/libfwupd/fwupd-release.c
+++ b/libfwupd/fwupd-release.c
@@ -337,7 +337,7 @@ fwupd_release_get_issues(FwupdRelease *self)
 /**
  * fwupd_release_add_issue:
  * @self: a #FwupdRelease
- * @issue: the update issue, e.g. `CVE-2019-12345`
+ * @issue: (not nullable): the update issue, e.g. `CVE-2019-12345`
  *
  * Adds an resolved issue to this release.
  *
@@ -378,7 +378,7 @@ fwupd_release_get_categories(FwupdRelease *self)
 /**
  * fwupd_release_add_category:
  * @self: a #FwupdRelease
- * @category: the update category, e.g. `X-EmbeddedController`
+ * @category: (not nullable): the update category, e.g. `X-EmbeddedController`
  *
  * Adds the update category.
  *
@@ -401,7 +401,7 @@ fwupd_release_add_category(FwupdRelease *self, const gchar *category)
 /**
  * fwupd_release_has_category:
  * @self: a #FwupdRelease
- * @category: the update category, e.g. `X-EmbeddedController`
+ * @category: (not nullable): the update category, e.g. `X-EmbeddedController`
  *
  * Finds out if the release has the update category.
  *
@@ -444,7 +444,7 @@ fwupd_release_get_checksums(FwupdRelease *self)
 /**
  * fwupd_release_add_checksum:
  * @self: a #FwupdRelease
- * @checksum: the update checksum
+ * @checksum: (not nullable): the update checksum
  *
  * Sets the update checksum.
  *
@@ -467,7 +467,7 @@ fwupd_release_add_checksum(FwupdRelease *self, const gchar *checksum)
 /**
  * fwupd_release_has_checksum:
  * @self: a #FwupdRelease
- * @checksum: the update checksum
+ * @checksum: (not nullable): the update checksum
  *
  * Finds out if the release has the update checksum.
  *
@@ -510,7 +510,7 @@ fwupd_release_get_tags(FwupdRelease *self)
 /**
  * fwupd_release_add_tag:
  * @self: a #FwupdRelease
- * @tag: the update tag, e.g. `vendor-factory-2021q1`
+ * @tag: (not nullable): the update tag, e.g. `vendor-factory-2021q1`
  *
  * Adds a specific release tag.
  *
@@ -533,7 +533,7 @@ fwupd_release_add_tag(FwupdRelease *self, const gchar *tag)
 /**
  * fwupd_release_has_tag:
  * @self: a #FwupdRelease
- * @tag: the update tag, e.g. `vendor-factory-2021q1`
+ * @tag: (not nullable): the update tag, e.g. `vendor-factory-2021q1`
  *
  * Finds out if the release has a specific tag.
  *
@@ -576,8 +576,8 @@ fwupd_release_get_metadata(FwupdRelease *self)
 /**
  * fwupd_release_add_metadata_item:
  * @self: a #FwupdRelease
- * @key: the key
- * @value: the value
+ * @key: (not nullable): the key
+ * @value: (not nullable): the value
  *
  * Sets a release metadata item.
  *
@@ -596,7 +596,7 @@ fwupd_release_add_metadata_item(FwupdRelease *self, const gchar *key, const gcha
 /**
  * fwupd_release_add_metadata:
  * @self: a #FwupdRelease
- * @hash: the key-values
+ * @hash: (not nullable): the key-values
  *
  * Sets multiple release metadata items.
  *
@@ -623,7 +623,7 @@ fwupd_release_add_metadata(FwupdRelease *self, GHashTable *hash)
 /**
  * fwupd_release_get_metadata_item:
  * @self: a #FwupdRelease
- * @key: the key
+ * @key: (not nullable): the key
  *
  * Gets a release metadata item.
  *
@@ -704,7 +704,7 @@ fwupd_release_get_locations(FwupdRelease *self)
 /**
  * fwupd_release_add_location:
  * @self: a #FwupdRelease
- * @location: the update URI
+ * @location: (not nullable): the update URI
  *
  * Adds an update URI, i.e. where you can download the firmware from.
  *
@@ -2269,7 +2269,7 @@ fwupd_release_set_from_variant_iter(FwupdRelease *self, GVariantIter *iter)
 
 /**
  * fwupd_release_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates a new release using serialized data.
  *
@@ -2302,7 +2302,7 @@ fwupd_release_from_variant(GVariant *value)
 
 /**
  * fwupd_release_array_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates an array of new releases using serialized data.
  *
diff --git a/libfwupd/fwupd-remote.c b/libfwupd/fwupd-remote.c
index ce3114418..c9c1ca374 100644
--- a/libfwupd/fwupd-remote.c
+++ b/libfwupd/fwupd-remote.c
@@ -420,7 +420,7 @@ fwupd_remote_set_security_report_uri(FwupdRemote *self, const gchar *security_re
 
 /**
  * fwupd_remote_kind_from_string:
- * @kind: a string, e.g. `download`
+ * @kind: (nullable): a string, e.g. `download`
  *
  * Converts an printable string to an enumerated type.
  *
@@ -591,7 +591,7 @@ fwupd_remote_setup(FwupdRemote *self, GError **error)
 /**
  * fwupd_remote_load_from_filename:
  * @self: a #FwupdRemote
- * @filename: a filename
+ * @filename: (not nullable): a filename
  * @cancellable: (nullable): optional #GCancellable
  * @error: (nullable): optional return location for an error
  *
@@ -1044,7 +1044,7 @@ fwupd_remote_get_checksum(FwupdRemote *self)
 /**
  * fwupd_remote_build_firmware_uri:
  * @self: a #FwupdRemote
- * @url: the URL to use
+ * @url: (not nullable): the URL to use
  * @error: (nullable): optional return location for an error
  *
  * Builds a URI for the URL using the username and password set for the remote,
@@ -1162,7 +1162,7 @@ fwupd_remote_load_signature_jcat(FwupdRemote *self, JcatFile *jcat_file, GError
 /**
  * fwupd_remote_load_signature_bytes:
  * @self: a #FwupdRemote
- * @bytes: data blob
+ * @bytes: (not nullable): data blob
  * @error: (nullable): optional return location for an error
  *
  * Parses the signature, updating the metadata URI as appropriate.
@@ -1203,7 +1203,7 @@ fwupd_remote_load_signature_bytes(FwupdRemote *self, GBytes *bytes, GError **err
 /**
  * fwupd_remote_load_signature:
  * @self: a #FwupdRemote
- * @filename: a filename
+ * @filename: (not nullable): a filename
  * @error: (nullable): optional return location for an error
  *
  * Parses the signature, updating the metadata URI as appropriate.
@@ -1718,7 +1718,7 @@ fwupd_remote_finalize(GObject *obj)
 
 /**
  * fwupd_remote_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates a new remote using serialized data.
  *
@@ -1751,7 +1751,7 @@ fwupd_remote_from_variant(GVariant *value)
 
 /**
  * fwupd_remote_array_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates an array of new devices using serialized data.
  *
diff --git a/libfwupd/fwupd-request.c b/libfwupd/fwupd-request.c
index 1f26144d2..b6c910c26 100644
--- a/libfwupd/fwupd-request.c
+++ b/libfwupd/fwupd-request.c
@@ -55,7 +55,7 @@ fwupd_request_kind_to_string(FwupdRequestKind kind)
 
 /**
  * fwupd_request_kind_from_string:
- * @kind: a string, e.g. `immediate`
+ * @kind: (nullable): a string, e.g. `immediate`
  *
  * Converts a string to an enumerated update message kind.
  *
@@ -538,10 +538,24 @@ fwupd_request_class_init(FwupdRequestClass *klass)
 	object_class->get_property = fwupd_request_get_property;
 	object_class->set_property = fwupd_request_set_property;
 
+	/**
+	 * FwupdRequest:id:
+	 *
+	 * The request identifier.
+	 *
+	 * Since: 1.6.2
+	 */
 	pspec =
 	    g_param_spec_string("id", NULL, NULL, NULL, G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_ID, pspec);
 
+	/**
+	 * FwupdRequest:kind:
+	 *
+	 * The kind of the request.
+	 *
+	 * Since: 1.6.2
+	 */
 	pspec = g_param_spec_uint("kind",
 				  NULL,
 				  NULL,
@@ -551,6 +565,13 @@ fwupd_request_class_init(FwupdRequestClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_KIND, pspec);
 
+	/**
+	 * FwupdRequest:message:
+	 *
+	 * The message text in the request.
+	 *
+	 * Since: 1.6.2
+	 */
 	pspec = g_param_spec_string("message",
 				    NULL,
 				    NULL,
@@ -558,6 +579,13 @@ fwupd_request_class_init(FwupdRequestClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_MESSAGE, pspec);
 
+	/**
+	 * FwupdRequest:image:
+	 *
+	 * The image link for the request.
+	 *
+	 * Since: 1.6.2
+	 */
 	pspec =
 	    g_param_spec_string("image", NULL, NULL, NULL, G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_IMAGE, pspec);
@@ -576,7 +604,7 @@ fwupd_request_set_from_variant_iter(FwupdRequest *self, GVariantIter *iter)
 
 /**
  * fwupd_request_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates a new request using serialized data.
  *
diff --git a/libfwupd/fwupd-security-attr.c b/libfwupd/fwupd-security-attr.c
index 02069cb1d..0dba11db0 100644
--- a/libfwupd/fwupd-security-attr.c
+++ b/libfwupd/fwupd-security-attr.c
@@ -71,7 +71,7 @@ fwupd_security_attr_flag_to_string(FwupdSecurityAttrFlags flag)
 
 /**
  * fwupd_security_attr_flag_from_string:
- * @flag: a string, e.g. `success`
+ * @flag: (nullable): a string, e.g. `success`
  *
  * Converts a string to an enumerated flag.
  *
@@ -141,7 +141,7 @@ fwupd_security_attr_result_to_string(FwupdSecurityAttrResult result)
 
 /**
  * fwupd_security_attr_result_from_string:
- * @result: a string, e.g. `not-encrypted`
+ * @result: (nullable): a string, e.g. `not-encrypted`
  *
  * Converts a string to an enumerated result.
  *
@@ -1253,7 +1253,7 @@ fwupd_security_attr_set_from_variant_iter(FwupdSecurityAttr *self, GVariantIter
 
 /**
  * fwupd_security_attr_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates a new security attribute using serialized data.
  *
@@ -1285,7 +1285,7 @@ fwupd_security_attr_from_variant(GVariant *value)
 
 /**
  * fwupd_security_attr_array_from_variant:
- * @value: the serialized data
+ * @value: (not nullable): the serialized data
  *
  * Creates an array of new security attributes using serialized data.
  *
diff --git a/libfwupdplugin/fu-backend.c b/libfwupdplugin/fu-backend.c
index 20f5c69ee..40ea50cde 100644
--- a/libfwupdplugin/fu-backend.c
+++ b/libfwupdplugin/fu-backend.c
@@ -363,6 +363,13 @@ fu_backend_class_init(FuBackendClass *klass)
 	object_class->finalize = fu_backend_finalize;
 	object_class->dispose = fu_backend_dispose;
 
+	/**
+	 * FuBackend:name:
+	 *
+	 * The backend name.
+	 *
+	 * Since: 1.6.1
+	 */
 	pspec =
 	    g_param_spec_string("name",
 				NULL,
@@ -371,6 +378,13 @@ fu_backend_class_init(FuBackendClass *klass)
 				G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_NAME, pspec);
 
+	/**
+	 * FuBackend:context:
+	 *
+	 * The #FuContent to use.
+	 *
+	 * Since: 1.6.1
+	 */
 	pspec =
 	    g_param_spec_object("context",
 				NULL,
@@ -379,6 +393,15 @@ fu_backend_class_init(FuBackendClass *klass)
 				G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_CONTEXT, pspec);
 
+	/**
+	 * FuBackend::device-added:
+	 * @self: the #FuBackend instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::device-added signal is emitted when a device has been added.
+	 *
+	 * Since: 1.6.1
+	 **/
 	signals[SIGNAL_ADDED] = g_signal_new("device-added",
 					     G_TYPE_FROM_CLASS(object_class),
 					     G_SIGNAL_RUN_LAST,
@@ -389,6 +412,15 @@ fu_backend_class_init(FuBackendClass *klass)
 					     G_TYPE_NONE,
 					     1,
 					     FU_TYPE_DEVICE);
+	/**
+	 * FuBackend::device-removed:
+	 * @self: the #FuBackend instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::device-removed signal is emitted when a device has been removed.
+	 *
+	 * Since: 1.6.1
+	 **/
 	signals[SIGNAL_REMOVED] = g_signal_new("device-removed",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,
@@ -399,6 +431,15 @@ fu_backend_class_init(FuBackendClass *klass)
 					       G_TYPE_NONE,
 					       1,
 					       FU_TYPE_DEVICE);
+	/**
+	 * FuBackend::device-changed:
+	 * @self: the #FuBackend instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::device-changed signal is emitted when a device has been changed.
+	 *
+	 * Since: 1.6.1
+	 **/
 	signals[SIGNAL_CHANGED] = g_signal_new("device-changed",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,
diff --git a/libfwupdplugin/fu-bluez-device.c b/libfwupdplugin/fu-bluez-device.c
index 10aa4cbb4..436be2601 100644
--- a/libfwupdplugin/fu-bluez-device.c
+++ b/libfwupdplugin/fu-bluez-device.c
@@ -669,6 +669,15 @@ fu_bluez_device_class_init(FuBluezDeviceClass *klass)
 	device_class->to_string = fu_bluez_device_to_string;
 	device_class->incorporate = fu_bluez_device_incorporate;
 
+	/**
+	 * FuBluezDevice::changed:
+	 * @self: the #FuBluezDevice instance that emitted the signal
+	 * @uuid: the UUID that changed
+	 *
+	 * The ::changed signal is emitted when a service with a specific UUID changed.
+	 *
+	 * Since: 1.5.8
+	 **/
 	signals[SIGNAL_CHANGED] = g_signal_new("changed",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,
@@ -680,6 +689,13 @@ fu_bluez_device_class_init(FuBluezDeviceClass *klass)
 					       1,
 					       G_TYPE_STRING);
 
+	/**
+	 * FuBluezDevice:object-manager:
+	 *
+	 * The object manager instance for all devices.
+	 *
+	 * Since: 1.5.8
+	 */
 	pspec = g_param_spec_object("object-manager",
 				    NULL,
 				    NULL,
@@ -687,6 +703,13 @@ fu_bluez_device_class_init(FuBluezDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_OBJECT_MANAGER, pspec);
 
+	/**
+	 * FuBluezDevice:proxy:
+	 *
+	 * The D-Bus proxy for the object.
+	 *
+	 * Since: 1.5.8
+	 */
 	pspec = g_param_spec_object("proxy",
 				    NULL,
 				    NULL,
diff --git a/libfwupdplugin/fu-cfi-device.c b/libfwupdplugin/fu-cfi-device.c
index 1dffdebe2..566452eae 100644
--- a/libfwupdplugin/fu-cfi-device.c
+++ b/libfwupdplugin/fu-cfi-device.c
@@ -498,6 +498,13 @@ fu_cfi_device_class_init(FuCfiDeviceClass *klass)
 	klass_device->to_string = fu_cfi_device_to_string;
 	klass_device->set_quirk_kv = fu_cfi_device_set_quirk_kv;
 
+	/**
+	 * FuCfiDevice:flash-id:
+	 *
+	 * The CCI JEDEC flash ID.
+	 *
+	 * Since: 1.7.1
+	 */
 	pspec = g_param_spec_string("flash-id",
 				    NULL,
 				    NULL,
diff --git a/libfwupdplugin/fu-common-version.c b/libfwupdplugin/fu-common-version.c
index b4d216e1b..798db1b62 100644
--- a/libfwupdplugin/fu-common-version.c
+++ b/libfwupdplugin/fu-common-version.c
@@ -237,7 +237,7 @@ _g_ascii_is_digits(const gchar *str)
 
 /**
  * fu_common_version_ensure_semver:
- * @version: a version number, e.g. ` V1.2.3 `
+ * @version: (nullable): a version number, e.g. ` V1.2.3 `
  *
  * Builds a semver from the possibly crazy version number.
  *
@@ -289,7 +289,7 @@ fu_common_version_ensure_semver(const gchar *version)
 
 /**
  * fu_common_version_parse_from_format
- * @version: a version number
+ * @version: (nullable): a version number
  * @fmt: a version format, e.g. %FWUPD_VERSION_FORMAT_TRIPLET
  *
  * Returns a dotted decimal version string from a version string using @fmt.
@@ -303,7 +303,7 @@ fu_common_version_ensure_semver(const gchar *version)
  * Anything with a `.` or that doesn't match `[0-9]` or `0x[a-f,0-9]` is considered
  * a string and returned without modification.
  *
- * Returns: a version number, e.g. `1.0.3`
+ * Returns: a version number, e.g. `1.0.3`, or %NULL on error
  *
  * Since: 1.3.3
  */
@@ -345,7 +345,7 @@ fu_common_version_parse_from_format(const gchar *version, FwupdVersionFormat fmt
 
 /**
  * fu_common_version_guess_format:
- * @version: a version number, e.g. `1.2.3`
+ * @version: (nullable): a version number, e.g. `1.2.3`
  *
  * Guesses the version format from the version number. This is only a heuristic
  * and plugins and components should explicitly set the version format whenever
@@ -412,7 +412,7 @@ fu_common_version_convert_base(FwupdVersionFormat fmt)
 
 /**
  * fu_common_version_verify_format:
- * @version: a string, e.g. `0x1234`
+ * @version: (not nullable): a string, e.g. `0x1234`
  * @fmt: a version format
  * @error: (nullable): optional return location for an error
  *
@@ -510,8 +510,8 @@ fu_common_vercmp_safe(const gchar *version_a, const gchar *version_b)
 
 /**
  * fu_common_vercmp_full:
- * @version_a: the semver release version, e.g. `1.2.3`
- * @version_b: the semver release version, e.g. `1.2.3.1`
+ * @version_a: (nullable): the semver release version, e.g. `1.2.3`
+ * @version_b: (nullable): the semver release version, e.g. `1.2.3.1`
  * @fmt: a version format, e.g. %FWUPD_VERSION_FORMAT_PLAIN
  *
  * Compares version numbers for sorting taking into account the version format
diff --git a/libfwupdplugin/fu-context.c b/libfwupdplugin/fu-context.c
index e9972bae1..f4ce20040 100644
--- a/libfwupdplugin/fu-context.c
+++ b/libfwupdplugin/fu-context.c
@@ -824,6 +824,13 @@ fu_context_class_init(FuContextClass *klass)
 	object_class->get_property = fu_context_get_property;
 	object_class->set_property = fu_context_set_property;
 
+	/**
+	 * FuContext:battery-state:
+	 *
+	 * The system battery state.
+	 *
+	 * Since: 1.6.0
+	 */
 	pspec = g_param_spec_uint("battery-state",
 				  NULL,
 				  NULL,
@@ -833,6 +840,13 @@ fu_context_class_init(FuContextClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_BATTERY_STATE, pspec);
 
+	/**
+	 * FuContext:lid-state:
+	 *
+	 * The system lid state.
+	 *
+	 * Since: 1.7.4
+	 */
 	pspec = g_param_spec_uint("lid-state",
 				  NULL,
 				  NULL,
@@ -842,6 +856,13 @@ fu_context_class_init(FuContextClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_LID_STATE, pspec);
 
+	/**
+	 * FuContext:battery-level:
+	 *
+	 * The system battery level in percent.
+	 *
+	 * Since: 1.6.0
+	 */
 	pspec = g_param_spec_uint("battery-level",
 				  NULL,
 				  NULL,
@@ -851,6 +872,13 @@ fu_context_class_init(FuContextClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_BATTERY_LEVEL, pspec);
 
+	/**
+	 * FuContext:battery-threshold:
+	 *
+	 * The system battery threshold in percent.
+	 *
+	 * Since: 1.6.0
+	 */
 	pspec = g_param_spec_uint("battery-threshold",
 				  NULL,
 				  NULL,
@@ -860,6 +888,15 @@ fu_context_class_init(FuContextClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_BATTERY_THRESHOLD, pspec);
 
+	/**
+	 * FuContext::security-changed:
+	 * @self: the #FuContext instance that emitted the signal
+	 *
+	 * The ::security-changed signal is emitted when some system state has changed that could
+	 * have affected the security level.
+	 *
+	 * Since: 1.6.0
+	 **/
 	signals[SIGNAL_SECURITY_CHANGED] =
 	    g_signal_new("security-changed",
 			 G_TYPE_FROM_CLASS(object_class),
diff --git a/libfwupdplugin/fu-device.c b/libfwupdplugin/fu-device.c
index 838013e08..84f82c969 100644
--- a/libfwupdplugin/fu-device.c
+++ b/libfwupdplugin/fu-device.c
@@ -4691,6 +4691,15 @@ fu_device_class_init(FuDeviceClass *klass)
 	object_class->get_property = fu_device_get_property;
 	object_class->set_property = fu_device_set_property;
 
+	/**
+	 * FuDevice::child-added:
+	 * @self: the #FuDevice instance that emitted the signal
+	 * @device: the #FuDevice child
+	 *
+	 * The ::child-added signal is emitted when a device has been added as a child.
+	 *
+	 * Since: 1.0.8
+	 **/
 	signals[SIGNAL_CHILD_ADDED] = g_signal_new("child-added",
 						   G_TYPE_FROM_CLASS(object_class),
 						   G_SIGNAL_RUN_LAST,
@@ -4701,6 +4710,15 @@ fu_device_class_init(FuDeviceClass *klass)
 						   G_TYPE_NONE,
 						   1,
 						   FU_TYPE_DEVICE);
+	/**
+	 * FuDevice::child-removed:
+	 * @self: the #FuDevice instance that emitted the signal
+	 * @device: the #FuDevice child
+	 *
+	 * The ::child-removed signal is emitted when a device has been removed as a child.
+	 *
+	 * Since: 1.0.8
+	 **/
 	signals[SIGNAL_CHILD_REMOVED] = g_signal_new("child-removed",
 						     G_TYPE_FROM_CLASS(object_class),
 						     G_SIGNAL_RUN_LAST,
@@ -4711,6 +4729,15 @@ fu_device_class_init(FuDeviceClass *klass)
 						     G_TYPE_NONE,
 						     1,
 						     FU_TYPE_DEVICE);
+	/**
+	 * FuDevice::request:
+	 * @self: the #FuDevice instance that emitted the signal
+	 * @request: the #FwupdRequest
+	 *
+	 * The ::request signal is emitted when the device needs interactive action from the user.
+	 *
+	 * Since: 1.6.2
+	 **/
 	signals[SIGNAL_REQUEST] = g_signal_new("request",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,
@@ -4722,6 +4749,13 @@ fu_device_class_init(FuDeviceClass *klass)
 					       1,
 					       FWUPD_TYPE_REQUEST);
 
+	/**
+	 * FuDevice:physical-id:
+	 *
+	 * The device physical ID.
+	 *
+	 * Since: 1.1.2
+	 */
 	pspec = g_param_spec_string("physical-id",
 				    NULL,
 				    NULL,
@@ -4729,6 +4763,13 @@ fu_device_class_init(FuDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_PHYSICAL_ID, pspec);
 
+	/**
+	 * FuDevice:logical-id:
+	 *
+	 * The device logical ID.
+	 *
+	 * Since: 1.1.2
+	 */
 	pspec = g_param_spec_string("logical-id",
 				    NULL,
 				    NULL,
@@ -4736,6 +4777,13 @@ fu_device_class_init(FuDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_LOGICAL_ID, pspec);
 
+	/**
+	 * FuDevice:backend-id:
+	 *
+	 * The device backend ID.
+	 *
+	 * Since: 1.5.8
+	 */
 	pspec = g_param_spec_string("backend-id",
 				    NULL,
 				    NULL,
@@ -4743,6 +4791,13 @@ fu_device_class_init(FuDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_BACKEND_ID, pspec);
 
+	/**
+	 * FuDevice:battery-level:
+	 *
+	 * The device battery level in percent.
+	 *
+	 * Since: 1.5.8
+	 */
 	pspec = g_param_spec_uint("battery-level",
 				  NULL,
 				  NULL,
@@ -4752,6 +4807,13 @@ fu_device_class_init(FuDeviceClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_BATTERY_LEVEL, pspec);
 
+	/**
+	 * FuDevice:battery-threshold:
+	 *
+	 * The device battery threshold in percent.
+	 *
+	 * Since: 1.5.8
+	 */
 	pspec = g_param_spec_uint("battery-threshold",
 				  NULL,
 				  NULL,
@@ -4761,6 +4823,13 @@ fu_device_class_init(FuDeviceClass *klass)
 				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_BATTERY_THRESHOLD, pspec);
 
+	/**
+	 * FuDevice:context:
+	 *
+	 * The #FuContext to use.
+	 *
+	 * Since: 1.6.0
+	 */
 	pspec = g_param_spec_object("context",
 				    NULL,
 				    NULL,
@@ -4768,6 +4837,13 @@ fu_device_class_init(FuDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_CONTEXT, pspec);
 
+	/**
+	 * FuDevice:proxy:
+	 *
+	 * The device proxy to use.
+	 *
+	 * Since: 1.4.1
+	 */
 	pspec = g_param_spec_object("proxy",
 				    NULL,
 				    NULL,
@@ -4775,6 +4851,13 @@ fu_device_class_init(FuDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_PROXY, pspec);
 
+	/**
+	 * FuDevice:parent:
+	 *
+	 * The device parent.
+	 *
+	 * Since: 1.0.8
+	 */
 	pspec = g_param_spec_object("parent",
 				    NULL,
 				    NULL,
diff --git a/libfwupdplugin/fu-hid-device.c b/libfwupdplugin/fu-hid-device.c
index a7fbf2db0..cf83c79c3 100644
--- a/libfwupdplugin/fu-hid-device.c
+++ b/libfwupdplugin/fu-hid-device.c
@@ -578,6 +578,13 @@ fu_hid_device_class_init(FuHidDeviceClass *klass)
 	klass_device->close = fu_hid_device_close;
 	klass_device->to_string = fu_hid_device_to_string;
 
+	/**
+	 * FuHidDevice:interface:
+	 *
+	 * The HID interface to use.
+	 *
+	 * Since: 1.4.0
+	 */
 	pspec = g_param_spec_uint("interface",
 				  NULL,
 				  NULL,
diff --git a/libfwupdplugin/fu-i2c-device.c b/libfwupdplugin/fu-i2c-device.c
index cda31a5b8..3662ef6ec 100644
--- a/libfwupdplugin/fu-i2c-device.c
+++ b/libfwupdplugin/fu-i2c-device.c
@@ -277,6 +277,13 @@ fu_i2c_device_class_init(FuI2cDeviceClass *klass)
 	klass_device->probe = fu_i2c_device_probe;
 	klass_device->to_string = fu_i2c_device_to_string;
 
+	/**
+	 * FuI2cDevice:bus-number:
+	 *
+	 * The I²C bus number.
+	 *
+	 * Since: 1.6.2
+	 */
 	pspec = g_param_spec_uint("bus-number",
 				  NULL,
 				  NULL,
diff --git a/libfwupdplugin/fu-plugin.c b/libfwupdplugin/fu-plugin.c
index c7662c4b8..6b71ed755 100644
--- a/libfwupdplugin/fu-plugin.c
+++ b/libfwupdplugin/fu-plugin.c
@@ -2369,6 +2369,16 @@ fu_plugin_class_init(FuPluginClass *klass)
 {
 	GObjectClass *object_class = G_OBJECT_CLASS(klass);
 	object_class->finalize = fu_plugin_finalize;
+
+	/**
+	 * FuPlugin::device-added:
+	 * @self: the #FuPlugin instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::device-added signal is emitted when a device has been added by the plugin.
+	 *
+	 * Since: 0.8.0
+	 **/
 	signals[SIGNAL_DEVICE_ADDED] = g_signal_new("device-added",
 						    G_TYPE_FROM_CLASS(object_class),
 						    G_SIGNAL_RUN_LAST,
@@ -2379,6 +2389,15 @@ fu_plugin_class_init(FuPluginClass *klass)
 						    G_TYPE_NONE,
 						    1,
 						    FU_TYPE_DEVICE);
+	/**
+	 * FuPlugin::device-removed:
+	 * @self: the #FuPlugin instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::device-removed signal is emitted when a device has been removed by the plugin.
+	 *
+	 * Since: 0.8.0
+	 **/
 	signals[SIGNAL_DEVICE_REMOVED] =
 	    g_signal_new("device-removed",
 			 G_TYPE_FROM_CLASS(object_class),
@@ -2390,6 +2409,15 @@ fu_plugin_class_init(FuPluginClass *klass)
 			 G_TYPE_NONE,
 			 1,
 			 FU_TYPE_DEVICE);
+	/**
+	 * FuPlugin::device-register:
+	 * @self: the #FuPlugin instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::device-register signal is emitted when another plugin has added the device.
+	 *
+	 * Since: 0.9.7
+	 **/
 	signals[SIGNAL_DEVICE_REGISTER] =
 	    g_signal_new("device-register",
 			 G_TYPE_FROM_CLASS(object_class),
@@ -2401,6 +2429,18 @@ fu_plugin_class_init(FuPluginClass *klass)
 			 G_TYPE_NONE,
 			 1,
 			 FU_TYPE_DEVICE);
+	/**
+	 * FuPlugin::check-supported:
+	 * @self: the #FuPlugin instance that emitted the signal
+	 * @guid: a device GUID
+	 *
+	 * The ::check-supported signal is emitted when a plugin wants to ask the daemon if a
+	 * specific device GUID is supported in the existing system metadata.
+	 *
+	 * Returns: %TRUE if the GUID is found
+	 *
+	 * Since: 1.0.0
+	 **/
 	signals[SIGNAL_CHECK_SUPPORTED] =
 	    g_signal_new("check-supported",
 			 G_TYPE_FROM_CLASS(object_class),
@@ -2421,6 +2461,15 @@ fu_plugin_class_init(FuPluginClass *klass)
 						     g_cclosure_marshal_VOID__VOID,
 						     G_TYPE_NONE,
 						     0);
+	/**
+	 * FuPlugin::config-changed:
+	 * @self: the #FuPlugin instance that emitted the signal
+	 *
+	 * The ::config-changed signal is emitted when one or more config files have changed which
+	 * may affect how the daemon should be run.
+	 *
+	 * Since: 1.7.0
+	 **/
 	signals[SIGNAL_CONFIG_CHANGED] =
 	    g_signal_new("config-changed",
 			 G_TYPE_FROM_CLASS(object_class),
diff --git a/libfwupdplugin/fu-progress.c b/libfwupdplugin/fu-progress.c
index 7c007f34d..db53d2952 100644
--- a/libfwupdplugin/fu-progress.c
+++ b/libfwupdplugin/fu-progress.c
@@ -885,6 +885,15 @@ fu_progress_class_init(FuProgressClass *klass)
 	GObjectClass *object_class = G_OBJECT_CLASS(klass);
 	object_class->finalize = fu_progress_finalize;
 
+	/**
+	 * FuProgress::percentage-changed:
+	 * @self: the #FuProgress instance that emitted the signal
+	 * @percentage: the new value
+	 *
+	 * The ::percentage-changed signal is emitted when the tasks completion has changed.
+	 *
+	 * Since: 1.7.0
+	 **/
 	signals[SIGNAL_PERCENTAGE_CHANGED] =
 	    g_signal_new("percentage-changed",
 			 G_TYPE_FROM_CLASS(object_class),
@@ -896,6 +905,15 @@ fu_progress_class_init(FuProgressClass *klass)
 			 G_TYPE_NONE,
 			 1,
 			 G_TYPE_UINT);
+	/**
+	 * FuProgress::status-changed:
+	 * @self: the #FuProgress instance that emitted the signal
+	 * @status: the new #FwupdStatus
+	 *
+	 * The ::status-changed signal is emitted when the task status has changed.
+	 *
+	 * Since: 1.7.0
+	 **/
 	signals[SIGNAL_STATUS_CHANGED] =
 	    g_signal_new("status-changed",
 			 G_TYPE_FROM_CLASS(object_class),
diff --git a/libfwupdplugin/fu-udev-device.c b/libfwupdplugin/fu-udev-device.c
index 6d4e281eb..d17a03e4e 100644
--- a/libfwupdplugin/fu-udev-device.c
+++ b/libfwupdplugin/fu-udev-device.c
@@ -2074,6 +2074,14 @@ fu_udev_device_class_init(FuUdevDeviceClass *klass)
 	device_class->bind_driver = fu_udev_device_bind_driver;
 	device_class->unbind_driver = fu_udev_device_unbind_driver;
 
+	/**
+	 * FuUdevDevice::changed:
+	 * @self: the #FuUdevDevice instance that emitted the signal
+	 *
+	 * The ::changed signal is emitted when the low-level GUdevDevice has changed.
+	 *
+	 * Since: 1.1.2
+	 **/
 	signals[SIGNAL_CHANGED] = g_signal_new("changed",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,
@@ -2084,6 +2092,13 @@ fu_udev_device_class_init(FuUdevDeviceClass *klass)
 					       G_TYPE_NONE,
 					       0);
 
+	/**
+	 * FuUdevDevice:udev-device:
+	 *
+	 * The low-level GUdevDevice.
+	 *
+	 * Since: 1.1.2
+	 */
 	pspec = g_param_spec_object("udev-device",
 				    NULL,
 				    NULL,
@@ -2091,6 +2106,13 @@ fu_udev_device_class_init(FuUdevDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_UDEV_DEVICE, pspec);
 
+	/**
+	 * FuUdevDevice:subsystem:
+	 *
+	 * The device subsystem.
+	 *
+	 * Since: 1.1.2
+	 */
 	pspec = g_param_spec_string("subsystem",
 				    NULL,
 				    NULL,
@@ -2098,6 +2120,13 @@ fu_udev_device_class_init(FuUdevDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_SUBSYSTEM, pspec);
 
+	/**
+	 * FuUdevDevice:bind-id:
+	 *
+	 * The bind ID to use when binding a new driver.
+	 *
+	 * Since: 1.7.2
+	 */
 	pspec = g_param_spec_string("bind-id",
 				    NULL,
 				    NULL,
@@ -2105,6 +2134,13 @@ fu_udev_device_class_init(FuUdevDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_BIND_ID, pspec);
 
+	/**
+	 * FuUdevDevice:driver:
+	 *
+	 * The driver being used for the device.
+	 *
+	 * Since: 1.5.3
+	 */
 	pspec = g_param_spec_string("driver",
 				    NULL,
 				    NULL,
@@ -2112,6 +2148,13 @@ fu_udev_device_class_init(FuUdevDeviceClass *klass)
 				    G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_DRIVER, pspec);
 
+	/**
+	 * FuUdevDevice:device-file:
+	 *
+	 * The low level file to use for device access.
+	 *
+	 * Since: 1.3.1
+	 */
 	pspec = g_param_spec_string("device-file",
 				    NULL,
 				    NULL,
diff --git a/libfwupdplugin/fu-usb-device.c b/libfwupdplugin/fu-usb-device.c
index 8dfcddd78..a0edcd391 100644
--- a/libfwupdplugin/fu-usb-device.c
+++ b/libfwupdplugin/fu-usb-device.c
@@ -722,6 +722,13 @@ fu_usb_device_class_init(FuUsbDeviceClass *klass)
 	device_class->bind_driver = fu_udev_device_bind_driver;
 	device_class->unbind_driver = fu_udev_device_unbind_driver;
 
+	/**
+	 * FuUsbDevice:usb-device:
+	 *
+	 * The low-level #GUsbDevice.
+	 *
+	 * Since: 1.0.2
+	 */
 	pspec = g_param_spec_object("usb-device",
 				    NULL,
 				    NULL,
diff --git a/libfwupdplugin/fu-volume.c b/libfwupdplugin/fu-volume.c
index 71c739b51..06665b2c5 100644
--- a/libfwupdplugin/fu-volume.c
+++ b/libfwupdplugin/fu-volume.c
@@ -94,6 +94,13 @@ fu_volume_class_init(FuVolumeClass *klass)
 	object_class->get_property = fu_volume_get_property;
 	object_class->set_property = fu_volume_set_property;
 
+	/**
+	 * FuVolume:proxy-block:
+	 *
+	 * The proxy for the block interface.
+	 *
+	 * Since: 1.4.6
+	 */
 	pspec =
 	    g_param_spec_object("proxy-block",
 				NULL,
@@ -102,6 +109,13 @@ fu_volume_class_init(FuVolumeClass *klass)
 				G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_PROXY_BLOCK, pspec);
 
+	/**
+	 * FuVolume:proxy-filesystem:
+	 *
+	 * The proxy for the filesystem interface.
+	 *
+	 * Since: 1.4.6
+	 */
 	pspec =
 	    g_param_spec_object("proxy-filesystem",
 				NULL,
@@ -110,6 +124,13 @@ fu_volume_class_init(FuVolumeClass *klass)
 				G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_PROXY_FILESYSTEM, pspec);
 
+	/**
+	 * FuVolume:mount-path:
+	 *
+	 * The UNIX mount path.
+	 *
+	 * Since: 1.4.6
+	 */
 	pspec =
 	    g_param_spec_string("mount-path",
 				NULL,
diff --git a/plugins/modem-manager/fu-mm-device.c b/plugins/modem-manager/fu-mm-device.c
index 8e7ec5545..d3087fccb 100644
--- a/plugins/modem-manager/fu-mm-device.c
+++ b/plugins/modem-manager/fu-mm-device.c
@@ -1642,6 +1642,12 @@ fu_mm_device_class_init(FuMmDeviceClass *klass)
 	klass_device->attach = fu_mm_device_attach;
 	klass_device->set_progress = fu_mm_device_set_progress;
 
+	/**
+	 * FuMmDevice::attach-finished:
+	 * @self: the #FuMmDevice instance that emitted the signal
+	 *
+	 * The ::attach-finished signal is emitted when the device has attached.
+	 **/
 	signals[SIGNAL_ATTACH_FINISHED] = g_signal_new("attach-finished",
 						       G_TYPE_FROM_CLASS(object_class),
 						       G_SIGNAL_RUN_LAST,
diff --git a/plugins/redfish/fu-redfish-device.c b/plugins/redfish/fu-redfish-device.c
index f54b635c1..7605a9d6c 100644
--- a/plugins/redfish/fu-redfish-device.c
+++ b/plugins/redfish/fu-redfish-device.c
@@ -843,6 +843,11 @@ fu_redfish_device_class_init(FuRedfishDeviceClass *klass)
 	klass_device->to_string = fu_redfish_device_to_string;
 	klass_device->probe = fu_redfish_device_probe;
 
+	/**
+	 * FuRedfishDevice:backend:
+	 *
+	 * The backend that added the device.
+	 */
 	pspec =
 	    g_param_spec_object("backend",
 				NULL,
@@ -851,6 +856,11 @@ fu_redfish_device_class_init(FuRedfishDeviceClass *klass)
 				G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_BACKEND, pspec);
 
+	/**
+	 * FuRedfishDevice:member:
+	 *
+	 * The JSON root member for the device.
+	 */
 	pspec =
 	    g_param_spec_pointer("member",
 				 NULL,
diff --git a/plugins/superio/fu-superio-device.c b/plugins/superio/fu-superio-device.c
index 25509a4bc..3da5b9de5 100644
--- a/plugins/superio/fu-superio-device.c
+++ b/plugins/superio/fu-superio-device.c
@@ -500,6 +500,12 @@ fu_superio_device_class_init(FuSuperioDeviceClass *klass)
 	/* properties */
 	object_class->get_property = fu_superio_device_get_property;
 	object_class->set_property = fu_superio_device_set_property;
+
+	/**
+	 * FuSuperioDevice:chipset:
+	 *
+	 * The SuperIO chipset name being used.
+	 */
 	pspec =
 	    g_param_spec_string("chipset",
 				NULL,
diff --git a/plugins/uefi-capsule/fu-uefi-device.c b/plugins/uefi-capsule/fu-uefi-device.c
index 4e58848e4..a7af363f9 100644
--- a/plugins/uefi-capsule/fu-uefi-device.c
+++ b/plugins/uefi-capsule/fu-uefi-device.c
@@ -795,6 +795,11 @@ fu_uefi_device_class_init(FuUefiDeviceClass *klass)
 	klass_device->get_results = fu_uefi_device_get_results;
 	klass_device->set_progress = fu_uefi_device_set_progress;
 
+	/**
+	 * FuUefiDevice:fw-class:
+	 *
+	 * The firmware class, i.e. the ESRT GUID.
+	 */
 	pspec =
 	    g_param_spec_string("fw-class",
 				NULL,
@@ -802,6 +807,12 @@ fu_uefi_device_class_init(FuUefiDeviceClass *klass)
 				NULL,
 				G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_FW_CLASS, pspec);
+
+	/**
+	 * FuUefiDevice:kind:
+	 *
+	 * The device kind.
+	 */
 	pspec = g_param_spec_uint("kind",
 				  NULL,
 				  NULL,
@@ -810,6 +821,12 @@ fu_uefi_device_class_init(FuUefiDeviceClass *klass)
 				  FU_UEFI_DEVICE_KIND_UNKNOWN,
 				  G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_KIND, pspec);
+
+	/**
+	 * FuUefiDevice:capsule-flags:
+	 *
+	 * The capsule flags to use for the update.
+	 */
 	pspec = g_param_spec_uint("capsule-flags",
 				  NULL,
 				  NULL,
@@ -818,6 +835,12 @@ fu_uefi_device_class_init(FuUefiDeviceClass *klass)
 				  0,
 				  G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_CAPSULE_FLAGS, pspec);
+
+	/**
+	 * FuUefiDevice:fw-version:
+	 *
+	 * The current firmware version.
+	 */
 	pspec = g_param_spec_uint("fw-version",
 				  NULL,
 				  NULL,
@@ -826,6 +849,12 @@ fu_uefi_device_class_init(FuUefiDeviceClass *klass)
 				  0,
 				  G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_FW_VERSION, pspec);
+
+	/**
+	 * FuUefiDevice:fw-version-lowest:
+	 *
+	 * The lowest possible installable version.
+	 */
 	pspec = g_param_spec_uint("fw-version-lowest",
 				  NULL,
 				  NULL,
@@ -834,6 +863,12 @@ fu_uefi_device_class_init(FuUefiDeviceClass *klass)
 				  0,
 				  G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_FW_VERSION_LOWEST, pspec);
+
+	/**
+	 * FuUefiDevice:last-attempt-status:
+	 *
+	 * The last attempt status value.
+	 */
 	pspec = g_param_spec_uint("last-attempt-status",
 				  NULL,
 				  NULL,
@@ -842,6 +877,12 @@ fu_uefi_device_class_init(FuUefiDeviceClass *klass)
 				  FU_UEFI_DEVICE_STATUS_SUCCESS,
 				  G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_LAST_ATTEMPT_STATUS, pspec);
+
+	/**
+	 * FuUefiDevice:last-attempt-version:
+	 *
+	 * The last attempt firmware version.
+	 */
 	pspec = g_param_spec_uint("last-attempt-version",
 				  NULL,
 				  NULL,
@@ -850,6 +891,12 @@ fu_uefi_device_class_init(FuUefiDeviceClass *klass)
 				  0,
 				  G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_LAST_ATTEMPT_VERSION, pspec);
+
+	/**
+	 * FuUefiDevice:fmp-hardware-instance:
+	 *
+	 * The FMP hardware instance.
+	 */
 	pspec =
 	    g_param_spec_uint64("fmp-hardware-instance",
 				NULL,
diff --git a/plugins/vli/fu-vli-device.c b/plugins/vli/fu-vli-device.c
index b6f4a0388..39aacf40c 100644
--- a/plugins/vli/fu-vli-device.c
+++ b/plugins/vli/fu-vli-device.c
@@ -697,6 +697,12 @@ fu_vli_device_class_init(FuVliDeviceClass *klass)
 	object_class->set_property = fu_vli_device_set_property;
 	object_class->constructed = fu_vli_device_constructed;
 	object_class->finalize = fu_vli_device_finalize;
+
+	/**
+	 * FuVliDevice:kind:
+	 *
+	 * The kind of VLI device.
+	 */
 	pspec = g_param_spec_uint("kind",
 				  NULL,
 				  NULL,
diff --git a/plugins/wacom-usb/fu-wac-module.c b/plugins/wacom-usb/fu-wac-module.c
index e67a23a88..b98bc6931 100644
--- a/plugins/wacom-usb/fu-wac-module.c
+++ b/plugins/wacom-usb/fu-wac-module.c
@@ -373,12 +373,24 @@ fu_wac_module_class_init(FuWacModuleClass *klass)
 	/* properties */
 	object_class->get_property = fu_wac_module_get_property;
 	object_class->set_property = fu_wac_module_set_property;
+
+	/**
+	 * FuWacModule:usb-device:
+	 *
+	 * The parent USB device to use.
+	 */
 	pspec = g_param_spec_object("usb-device",
 				    NULL,
 				    NULL,
 				    G_USB_TYPE_DEVICE,
 				    G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_NAME);
 	g_object_class_install_property(object_class, PROP_USB_DEVICE, pspec);
+
+	/**
+	 * FuWacModule:fw-type:
+	 *
+	 * The firmware kind.
+	 */
 	pspec = g_param_spec_uint("fw-type",
 				  NULL,
 				  NULL,
diff --git a/src/fu-config.c b/src/fu-config.c
index 29b115517..b85cd2935 100644
--- a/src/fu-config.c
+++ b/src/fu-config.c
@@ -367,6 +367,13 @@ fu_config_class_init(FuConfigClass *klass)
 	GObjectClass *object_class = G_OBJECT_CLASS(klass);
 	object_class->finalize = fu_config_finalize;
 
+	/**
+	 * FuConfig::changed:
+	 * @self: the #FuConfig instance that emitted the signal
+	 *
+	 * The ::changed signal is emitted when the config file has
+	 * changed, for instance when a parameter has been modified.
+	 **/
 	signals[SIGNAL_CHANGED] = g_signal_new("changed",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,
diff --git a/src/fu-device-list.c b/src/fu-device-list.c
index 54141da56..dc914b377 100644
--- a/src/fu-device-list.c
+++ b/src/fu-device-list.c
@@ -986,6 +986,13 @@ fu_device_list_class_init(FuDeviceListClass *klass)
 	GObjectClass *object_class = G_OBJECT_CLASS(klass);
 	object_class->finalize = fu_device_list_finalize;
 
+	/**
+	 * FuDeviceList::added:
+	 * @self: the #FuDeviceList instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::added signal is emitted when a device has been added to the list.
+	 **/
 	signals[SIGNAL_ADDED] = g_signal_new("added",
 					     G_TYPE_FROM_CLASS(object_class),
 					     G_SIGNAL_RUN_LAST,
@@ -996,6 +1003,13 @@ fu_device_list_class_init(FuDeviceListClass *klass)
 					     G_TYPE_NONE,
 					     1,
 					     FU_TYPE_DEVICE);
+	/**
+	 * FuDeviceList::removed:
+	 * @self: the #FuDeviceList instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::removed signal is emitted when a device has been removed from the list.
+	 **/
 	signals[SIGNAL_REMOVED] = g_signal_new("removed",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,
@@ -1006,6 +1020,13 @@ fu_device_list_class_init(FuDeviceListClass *klass)
 					       G_TYPE_NONE,
 					       1,
 					       FU_TYPE_DEVICE);
+	/**
+	 * FuDeviceList::changed:
+	 * @self: the #FuDeviceList instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::changed signal is emitted when a device has changed.
+	 **/
 	signals[SIGNAL_CHANGED] = g_signal_new("changed",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,
diff --git a/src/fu-engine.c b/src/fu-engine.c
index 94fafcf9b..03a896a5b 100644
--- a/src/fu-engine.c
+++ b/src/fu-engine.c
@@ -7045,6 +7045,13 @@ fu_engine_class_init(FuEngineClass *klass)
 	GObjectClass *object_class = G_OBJECT_CLASS(klass);
 	object_class->finalize = fu_engine_finalize;
 
+	/**
+	 * FuEngine::changed:
+	 * @self: the #FuEngine instance that emitted the signal
+	 *
+	 * The ::changed signal is emitted when the engine has changed, for instance when a device
+	 * state has been modified.
+	 **/
 	signals[SIGNAL_CHANGED] = g_signal_new("changed",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,
@@ -7054,6 +7061,13 @@ fu_engine_class_init(FuEngineClass *klass)
 					       g_cclosure_marshal_VOID__VOID,
 					       G_TYPE_NONE,
 					       0);
+	/**
+	 * FuEngine::device-added:
+	 * @self: the #FuEngine instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::device-added signal is emitted when a device has been added.
+	 **/
 	signals[SIGNAL_DEVICE_ADDED] = g_signal_new("device-added",
 						    G_TYPE_FROM_CLASS(object_class),
 						    G_SIGNAL_RUN_LAST,
@@ -7064,6 +7078,13 @@ fu_engine_class_init(FuEngineClass *klass)
 						    G_TYPE_NONE,
 						    1,
 						    FU_TYPE_DEVICE);
+	/**
+	 * FuEngine::device-removed:
+	 * @self: the #FuEngine instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::device-removed signal is emitted when a device has been removed.
+	 **/
 	signals[SIGNAL_DEVICE_REMOVED] = g_signal_new("device-removed",
 						      G_TYPE_FROM_CLASS(object_class),
 						      G_SIGNAL_RUN_LAST,
@@ -7074,6 +7095,13 @@ fu_engine_class_init(FuEngineClass *klass)
 						      G_TYPE_NONE,
 						      1,
 						      FU_TYPE_DEVICE);
+	/**
+	 * FuEngine::device-changed:
+	 * @self: the #FuEngine instance that emitted the signal
+	 * @device: the #FuDevice
+	 *
+	 * The ::device-changed signal is emitted when a device has been changed.
+	 **/
 	signals[SIGNAL_DEVICE_CHANGED] = g_signal_new("device-changed",
 						      G_TYPE_FROM_CLASS(object_class),
 						      G_SIGNAL_RUN_LAST,
@@ -7084,6 +7112,14 @@ fu_engine_class_init(FuEngineClass *klass)
 						      G_TYPE_NONE,
 						      1,
 						      FU_TYPE_DEVICE);
+	/**
+	 * FuEngine::device-request:
+	 * @self: the #FuEngine instance that emitted the signal
+	 * @request: the #FwupdRequest
+	 *
+	 * The ::device-request signal is emitted when the engine has asked the front end for an
+	 * interactive request.
+	 **/
 	signals[SIGNAL_DEVICE_REQUEST] = g_signal_new("device-request",
 						      G_TYPE_FROM_CLASS(object_class),
 						      G_SIGNAL_RUN_LAST,
@@ -7094,6 +7130,13 @@ fu_engine_class_init(FuEngineClass *klass)
 						      G_TYPE_NONE,
 						      1,
 						      FWUPD_TYPE_REQUEST);
+	/**
+	 * FuEngine::status-changed:
+	 * @self: the #FuEngine instance that emitted the signal
+	 * @status: the #FwupdStatus
+	 *
+	 * The ::status-changed signal is emitted when the daemon global status has changed.
+	 **/
 	signals[SIGNAL_STATUS_CHANGED] = g_signal_new("status-changed",
 						      G_TYPE_FROM_CLASS(object_class),
 						      G_SIGNAL_RUN_LAST,
diff --git a/src/fu-idle.c b/src/fu-idle.c
index 828ab2489..a2ca12afb 100644
--- a/src/fu-idle.c
+++ b/src/fu-idle.c
@@ -195,6 +195,11 @@ fu_idle_class_init(FuIdleClass *klass)
 	object_class->get_property = fu_idle_get_property;
 	object_class->set_property = fu_idle_set_property;
 
+	/**
+	 * FuIdle:status:
+	 *
+	 * The status of the idle monitor.
+	 */
 	pspec = g_param_spec_uint("status",
 				  NULL,
 				  NULL,
diff --git a/src/fu-remote-list.c b/src/fu-remote-list.c
index 5111fa816..19a5fc060 100644
--- a/src/fu-remote-list.c
+++ b/src/fu-remote-list.c
@@ -520,6 +520,13 @@ fu_remote_list_class_init(FuRemoteListClass *klass)
 	GObjectClass *object_class = G_OBJECT_CLASS(klass);
 	object_class->finalize = fu_remote_list_finalize;
 
+	/**
+	 * FuRemoteList::changed:
+	 * @self: the #FuRemoteList instance that emitted the signal
+	 *
+	 * The ::changed signal is emitted when the list of remotes has
+	 * changed, for instance when a remote has been added or removed.
+	 **/
 	signals[SIGNAL_CHANGED] = g_signal_new("changed",
 					       G_TYPE_FROM_CLASS(object_class),
 					       G_SIGNAL_RUN_LAST,