$ git clone -n https://src.fedoraproject.org/rpms/pkgtreediff.git /var/lib/mock/f40-build-745018-111932/root/chroot_tmpdir/scmroot/pkgtreediff
Cloning into '/var/lib/mock/f40-build-745018-111932/root/chroot_tmpdir/scmroot/pkgtreediff'...
$ git fetch origin 144de877d3f45e01e368891c0b79127360f891fc:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pkgtreediff
 * [new ref]         144de877d3f45e01e368891c0b79127360f891fc -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 144de87 bump release