diff --git a/src/PVE/APIServer/AnyEvent.pm b/src/PVE/APIServer/AnyEvent.pm
index f6e413b..a5f6681 100644
--- a/src/PVE/APIServer/AnyEvent.pm
+++ b/src/PVE/APIServer/AnyEvent.pm
@@ -430,6 +430,7 @@ my $file_extension_info = {
     oga => { ct => 'audio/ogg', nocomp => 1 },
     tgz => { ct => 'application/x-compressed-tar', nocomp => 1 },
     wasm => { ct => 'application/wasm' },
+    mo => { ct => 'application/x-gettext-translation' },
 };
 
 sub send_file_start {