$ git clone -n https://src.fedoraproject.org/rpms/R-fs.git /var/lib/mock/f40-build-789455-135730/root/chroot_tmpdir/scmroot/R-fs
Cloning into '/var/lib/mock/f40-build-789455-135730/root/chroot_tmpdir/scmroot/R-fs'...
$ git fetch origin 4cdc9e91703483d070b3f8a9b9202bcdf4d5f7a9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-fs
 * [new ref]         4cdc9e91703483d070b3f8a9b9202bcdf4d5f7a9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4cdc9e9 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild