$ git clone -n https://src.fedoraproject.org/rpms/cosmic-session.git /var/lib/mock/f45-build-39670-750/root/chroot_tmpdir/scmroot/cosmic-session
Cloning into '/var/lib/mock/f45-build-39670-750/root/chroot_tmpdir/scmroot/cosmic-session'...
$ git fetch origin 5185494283a8a4ae0a5fbe135decf43272a1ceca:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cosmic-session
 * [new ref]         5185494283a8a4ae0a5fbe135decf43272a1ceca -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5185494 Update to 1.6.0