gnome.org is temporarily forbidden in UUIDs, to avoid people copy-pasting
it around. For this reason, I setup a repo at github and modified
the UUID accordingly.
I still think that primary development will stay at gnome.org, although
I'll keep both updated.
GNOME Shell emits a warning when "url" is absent in metadata.json,
adding it costs nothing. Links to the GIT repository because I
found no better page to reference.
Giovanni Campagna