$ git clone -n https://src.fedoraproject.org/rpms/rpkg.git /var/lib/mock/f39-build-1602629-38571/root/chroot_tmpdir/scmroot/rpkg
Cloning into '/var/lib/mock/f39-build-1602629-38571/root/chroot_tmpdir/scmroot/rpkg'...
$ git fetch origin 8f19656c15080b05778e334b6c423221fe3ea4ce:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rpkg
 * [new ref]         8f19656c15080b05778e334b6c423221fe3ea4ce -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8f19656 Patches for lookaside retries