$ git clone -n https://src.fedoraproject.org/rpms/gnome-shell.git /var/lib/mock/f40-build-797471-141353/root/chroot_tmpdir/scmroot/gnome-shell
Cloning into '/var/lib/mock/f40-build-797471-141353/root/chroot_tmpdir/scmroot/gnome-shell'...
$ git fetch origin 69b455e2a3be5a32755e1bf28f454559c7678004:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-shell
 * [new ref]         69b455e2a3be5a32755e1bf28f454559c7678004 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 69b455e Update to 46.0