$ git clone -n https://src.fedoraproject.org/rpms/mirrorlist-server.git /var/lib/mock/f40-build-746541-112718/root/chroot_tmpdir/scmroot/mirrorlist-server
Cloning into '/var/lib/mock/f40-build-746541-112718/root/chroot_tmpdir/scmroot/mirrorlist-server'...
$ git fetch origin d6ff170c955550c08d8cf963ec3d475ea1023a52:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mirrorlist-server
 * [new ref]         d6ff170c955550c08d8cf963ec3d475ea1023a52 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d6ff170 Update to version 3.0.7; Fixes RHBZ#2128874