$ git clone -n https://src.fedoraproject.org/rpms/R-rex.git /var/lib/mock/f38-build-side-42-init-devel-869991-28441/root/chroot_tmpdir/scmroot/R-rex
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-869991-28441/root/chroot_tmpdir/scmroot/R-rex'...
$ git fetch origin 79a48ab50cc00cbf0b76043038380ccbaaaed7f5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-rex
 * [new ref]         79a48ab50cc00cbf0b76043038380ccbaaaed7f5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 79a48ab Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild