$ git clone -n https://src.fedoraproject.org/rpms/gnome-shell.git /var/lib/mock/f40-build-1736739-24671/root/chroot_tmpdir/scmroot/gnome-shell
Cloning into '/var/lib/mock/f40-build-1736739-24671/root/chroot_tmpdir/scmroot/gnome-shell'...
$ git fetch origin 38b8a35d5b841729aee1a8aa5df25000bbbc8213:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-shell
 * [new ref]         38b8a35d5b841729aee1a8aa5df25000bbbc8213 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 38b8a35 Update to 46.3.1