Sorry should have been a little more detailed.
The downloadable source code package (v1.6) does in fact contain the url and widget alternates modules.
On my production server, on which I installed the downloadable non-source (11MB) zip, those two modules appear to be missing.
Since they're not available in the Orchard gallery I just packaged them up myself from my source environment and deployed.
However I imagine they probably should have been included in the downloadable non-source zip package yes?