For anyone following the development of xdg-app, all development have now moved to freedesktop.org. Here is where things are happening now:
- Mailing list: http://lists.freedesktop.org/mailman/listinfo/xdg-app
- IRC: #xdg-app on freenode
- Git: git://anongit.freedesktop.org/xdg-app/xdg-app
- Releases: http://www.freedesktop.org/software/xdg-app/releases/
- Bugzilla: https://bugs.freedesktop.org/ (product xdg-app)