$ git clone -n https://src.fedoraproject.org/rpms/R-htmltools.git /var/lib/mock/f38-build-side-42-init-devel-962194-28791/root/chroot_tmpdir/scmroot/R-htmltools
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-962194-28791/root/chroot_tmpdir/scmroot/R-htmltools'...
$ git fetch origin a42896c9d72315c21054d80a4d89034f778a9516:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-htmltools
 * [new ref]         a42896c9d72315c21054d80a4d89034f778a9516 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a42896c update to 0.5.4