Originally reported at https://bugs.debian.org/110054 . See the similar glib issue

gobject-introspection 1.83 emits a new doc:format.

In Debian, libadwaita was built against this new gobject-introspection which means that /usr/share/gir1.0/Adw-1.gir contains <doc:format name="unknown"/>

The gir command now fails when trying to process rust-libadwaita.

gir -o .
Error: "GirXml: ./Adw-1.gir at line 14:3: Unexpected element <format>"

If you are able to build Debian packages easily, then this error can be seen by trying to build rust-libadwaita in Debian Unstable.