$ git clone -n https://src.fedoraproject.org/rpms/R-blob.git /var/lib/mock/f38-build-side-42-init-devel-805522-28190/root/chroot_tmpdir/scmroot/R-blob
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-805522-28190/root/chroot_tmpdir/scmroot/R-blob'...
$ git fetch origin 637db09d18b08eb334ca391c99b2254ad69806c2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-blob
 * [new ref]         637db09d18b08eb334ca391c99b2254ad69806c2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 637db09 Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild