$ git clone -n https://src.fedoraproject.org/rpms/ghc-gi-atk.git /var/lib/mock/f38-build-side-42-init-devel-917296-28734/root/chroot_tmpdir/scmroot/ghc-gi-atk
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-917296-28734/root/chroot_tmpdir/scmroot/ghc-gi-atk'...
$ git fetch origin 8209e0c9b3f311c3bab557d3a23711b5147a8e9b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-gi-atk
 * [new ref]         8209e0c9b3f311c3bab557d3a23711b5147a8e9b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8209e0c rebuild