$ git clone -n https://src.fedoraproject.org/rpms/R-rlang.git /var/lib/mock/f40-build-789547-135900/root/chroot_tmpdir/scmroot/R-rlang
Cloning into '/var/lib/mock/f40-build-789547-135900/root/chroot_tmpdir/scmroot/R-rlang'...
$ git fetch origin 51caaf23897fdb20ec5c85d5ef3b265e38edde7a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-rlang
 * [new ref]         51caaf23897fdb20ec5c85d5ef3b265e38edde7a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 51caaf2 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild