$ git clone -n https://src.fedoraproject.org/rpms/R-assertthat.git /var/lib/mock/f39-build-1535990-36254/root/chroot_tmpdir/scmroot/R-assertthat
Cloning into '/var/lib/mock/f39-build-1535990-36254/root/chroot_tmpdir/scmroot/R-assertthat'...
$ git fetch origin 60ce4e602735035d94ef391daa6ab4f7f254e53c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-assertthat
 * [new ref]         60ce4e602735035d94ef391daa6ab4f7f254e53c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 60ce4e6 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild