A few months ago, I switched from Gentoo to Debian. I used to
install/test the development version of Gnome when it reached the API/UI
freeze. Gentoo has the "Gentoo Gnome Overlay"  where Gnome packages
are tested before going into the main Portage repository.
Is there something similar with Debian? I have not seen any 2.21
packages in experimental yet. "Debian GNOME Packaging"  does not seem
to have them yet.
P.S. Please, do not forget to CC me as I did not subscribe to the list.