$ git clone -n https://src.fedoraproject.org/rpms/ghc-cereal.git /var/lib/mock/f38-build-side-42-init-devel-641516-26393/root/chroot_tmpdir/scmroot/ghc-cereal
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-641516-26393/root/chroot_tmpdir/scmroot/ghc-cereal'...
$ git fetch origin fa7f1a4c62aa1d149ce032ad611e60d362c081d1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-cereal
 * [new ref]         fa7f1a4c62aa1d149ce032ad611e60d362c081d1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fa7f1a4 Convert to %autorelease and %autochangelog