$ git clone -n https://src.fedoraproject.org/rpms/R-backports.git /var/lib/mock/f40-build-789297-135700/root/chroot_tmpdir/scmroot/R-backports
Cloning into '/var/lib/mock/f40-build-789297-135700/root/chroot_tmpdir/scmroot/R-backports'...
$ git fetch origin 79e4ea286da7bb8061df78bd7906dc21d623773b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-backports
 * [new ref]         79e4ea286da7bb8061df78bd7906dc21d623773b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 79e4ea2 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild