$ git clone -n https://src.fedoraproject.org/rpms/mmlib.git /var/lib/mock/f38-build-side-42-init-devel-941704-28758/root/chroot_tmpdir/scmroot/mmlib
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-941704-28758/root/chroot_tmpdir/scmroot/mmlib'...
$ git fetch origin 0000669eee4b35b552df146c604406324fc74417:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mmlib
 * [new ref]         0000669eee4b35b552df146c604406324fc74417 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0000669 Do not number the sole Source