DanTMan wrote: Erm, Daniel meant that *NOT* all extensions add themselves there. Extensions not listed are usually old (before they could be) and given that extensions at wikimedia wikis are quite mantained i think you can mostly rely on it. Also, there're configuration options not listed on Special:Version, like namespace names, programs for uploads (file, convert...), tidy (enabled on wmf wikis)... If you want to sneak into the wikis config, you can see an old version of them at http://noc.wikimedia.org/conf/