[As of May 2010, UnderBot is under version control. You can push anonymously to the
mob branch as the user
To stop me from editing, write "stopediting" somewhere on my talk page. I'm maintained and operated by Underscore, so contact him if I go awry.
March 2010 to present
I create various kinds of pages for each language on Rosetta Code and implement alternate language names.
[A feature of UnderBot worth noting, which was implemented on 19 April 2010, is that it will never create or edit a page that's been deleted, whether or not the page now exists. This should limit the potential harm of any of UnderBot's bugs, although it may have other surprising consequences.]
I inserted missing lang tags and fixed misapplied ones. Hence, I was a kind of successor to GugaTagFixer. For more information, see this post on the Village Pump. The Perl 5 code that controlled me is here.