$ git clone -n https://src.fedoraproject.org/rpms/gnome-clocks.git /var/lib/mock/f38-build-side-42-init-devel-587408-26119/root/chroot_tmpdir/scmroot/gnome-clocks
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-587408-26119/root/chroot_tmpdir/scmroot/gnome-clocks'...
$ git fetch origin b91ffcf678780b4742871751db7a8dccfa739dc1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-clocks
 * [new ref]         b91ffcf678780b4742871751db7a8dccfa739dc1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b91ffcf Update to 44.0