Technical information
Tools to make Wikipedia work better.
Catalogue of CSS classes used on the English Wikipedia
Editing articles of such length that you can't edit them
The MediaWiki software
MediaWiki User hub - help with installation and configuration of the MediaWiki software that runs Wikipedia, for those looking to set up their own wiki.
MediaWiki User's Guide - help with general use of the MediaWiki software that runs Wikipedia
Wikipedia:Village pump (technical)
Requests and bug reports
Browser notes
Download Wikipedia content - how to download Wikipedia and Wikimedia content
Export page(s) in XML
Computer help desk - Help with computers and software generally (i.e. not related to Wikipedia)