$ git clone -n https://src.fedoraproject.org/rpms/gnome-flashback.git /var/lib/mock/f40-build-2192304-51450/root/chroot_tmpdir/scmroot/gnome-flashback
Cloning into '/var/lib/mock/f40-build-2192304-51450/root/chroot_tmpdir/scmroot/gnome-flashback'...
$ git fetch origin a190d944f69404bf3f4e81928c31e86cfac90d9e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-flashback
 * [new ref]         a190d944f69404bf3f4e81928c31e86cfac90d9e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a190d94 Rebuild due rh#2251474