$ git clone -n https://src.fedoraproject.org/rpms/hamcrest.git /var/lib/mock/f41-build-1146698-21201/root/chroot_tmpdir/scmroot/hamcrest
Cloning into '/var/lib/mock/f41-build-1146698-21201/root/chroot_tmpdir/scmroot/hamcrest'...
$ git fetch origin 4e2c7401fdb2c0cbb4e442ac826e64b7dd29d1bb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/hamcrest
 * [new ref]         4e2c7401fdb2c0cbb4e442ac826e64b7dd29d1bb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4e2c740 Switch to a newer %patch syntax