$ git clone -n https://src.fedoraproject.org/rpms/R-rlang.git /var/lib/mock/f38-build-side-42-init-devel-584796-26107/root/chroot_tmpdir/scmroot/R-rlang
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-584796-26107/root/chroot_tmpdir/scmroot/R-rlang'...
$ git fetch origin bb9778f5e880504dc74db5a4481c920aad96e644:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-rlang
 * [new ref]         bb9778f5e880504dc74db5a4481c920aad96e644 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bb9778f Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild