This is probably the very last release before 2.28.0 which will happen very soon.
Gio:
* Removed Application, ApplicationCommandLine, and ActionGroup because
they are unfinished. We hope to add them back in glibmm 3.2.
* Removed SettingsBackend because it is unfinished.
* Settings: Removed API that used SettingsBackend.
* Variant: Improved the documentation.
Build: Remove the dependency on mm-common during the tarball build.
