$ git clone -n https://src.fedoraproject.org/rpms/R-knitr.git /var/lib/mock/f38-build-side-42-init-devel-743570-27658/root/chroot_tmpdir/scmroot/R-knitr
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-743570-27658/root/chroot_tmpdir/scmroot/R-knitr'...
$ git fetch origin ad54488fb99265e639a0fc310c7db438ac6cffd7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-knitr
 * [new ref]         ad54488fb99265e639a0fc310c7db438ac6cffd7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ad54488 Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild