$ git clone -n https://src.fedoraproject.org/rpms/gnome-desktop-testing.git /var/lib/mock/f45-build-11388-430/root/chroot_tmpdir/scmroot/gnome-desktop-testing
Cloning into '/var/lib/mock/f45-build-11388-430/root/chroot_tmpdir/scmroot/gnome-desktop-testing'...
$ git fetch origin b16a8288b177db5900c9e077006f9903a606d11a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-desktop-testing
 * [new ref]         b16a8288b177db5900c9e077006f9903a606d11a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b16a828 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild