$ git clone -n https://src.fedoraproject.org/rpms/hydra.git /var/lib/mock/f39-build-1584830-38142/root/chroot_tmpdir/scmroot/hydra
Cloning into '/var/lib/mock/f39-build-1584830-38142/root/chroot_tmpdir/scmroot/hydra'...
$ git fetch origin 930aa2c82464a5a6e0ba45310b071667c840c6b3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/hydra
 * [new ref]         930aa2c82464a5a6e0ba45310b071667c840c6b3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 930aa2c fix date