$ git clone -n https://src.fedoraproject.org/rpms/R-callr.git /var/lib/mock/f38-build-side-42-init-devel-818175-28339/root/chroot_tmpdir/scmroot/R-callr
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-818175-28339/root/chroot_tmpdir/scmroot/R-callr'...
$ git fetch origin 4ac8b21086fa2b691546452f58cb0b57a23cf8ea:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-callr
 * [new ref]         4ac8b21086fa2b691546452f58cb0b57a23cf8ea -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4ac8b21 Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild