I was just sorting out my blog in Google Webmaster as Google was throwing an error with what I had entered (not with the sitemap itself) and I realised that it allowed me to enter a sitemap url with a ? in it:

/index.php?tempskin=_sitemap

I am sure that I have had problems with this before and then I remembered that there are a couple of sitemap stub files in the distribution to get around problems with ? in the url.

So, if these files were included because of Google Webmaster then maybe they could be removed from the next release as Google doesn't seem to have a problem with it any more. If there was another reason they were included (or they need to be there for backwards compatibility) then ignore everything I have said :D