$ git clone -n https://src.fedoraproject.org/rpms/megatools.git /var/lib/mock/f42-build-60939026-6585972/root/chroot_tmpdir/scmroot/megatools
Cloning into '/var/lib/mock/f42-build-60939026-6585972/root/chroot_tmpdir/scmroot/megatools'...
$ git fetch origin 86ec4451f9d8219aa4f979b14afc0d8624f2ac77:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/megatools
 * [new ref]         86ec4451f9d8219aa4f979b14afc0d8624f2ac77 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 86ec445 rhbz#2376577