$ git clone -n https://src.fedoraproject.org/rpms/libburn1.git /var/lib/mock/f39-build-2507240-61701/root/chroot_tmpdir/scmroot/libburn1
Cloning into '/var/lib/mock/f39-build-2507240-61701/root/chroot_tmpdir/scmroot/libburn1'...
$ git fetch origin fe89396c67894a71ffaec146a7cf0fe2661de883:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libburn1
 * [new ref]         fe89396c67894a71ffaec146a7cf0fe2661de883 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fe89396 Added the README