$ git clone -n https://src.fedoraproject.org/rpms/mbox-importer.git /var/lib/mock/f43-build-side-115065-61057003-6588289/root/chroot_tmpdir/scmroot/mbox-importer
Cloning into '/var/lib/mock/f43-build-side-115065-61057003-6588289/root/chroot_tmpdir/scmroot/mbox-importer'...
$ git fetch origin 6e90297e0b4c358d57bd6f2e52ad515911d00d9a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mbox-importer
 * [new ref]         6e90297e0b4c358d57bd6f2e52ad515911d00d9a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6e90297 25.07.80