$ git clone -n https://src.fedoraproject.org/rpms/fedora-upgrade.git /var/lib/mock/f45-build-8873-396/root/chroot_tmpdir/scmroot/fedora-upgrade
Cloning into '/var/lib/mock/f45-build-8873-396/root/chroot_tmpdir/scmroot/fedora-upgrade'...
$ git fetch origin 8ec44081691d745969c17b10d50635ec6d6074a7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fedora-upgrade
 * [new ref]         8ec44081691d745969c17b10d50635ec6d6074a7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8ec4408 Update fedora-upgrade to 45.1-1