(written from a Production point of view)
Pages in this category are automatically added here by the MediaWiki parser when it detects they are over the limit of calls to "expensive parser functions" (most commonly #ifexist and PAGESINCATEGORY). See also: Special:ParserSpeed.
Pages in category "Memory Alpha pages with too many expensive parser function calls"
The following 30 pages are in this category, out of 30 total.