Help:Tracking categories

Tracking categories are a feature of MediaWiki that allows pages with certain characteristics to be tracked. It works by adding any such page to a category automatically.

Since MediaWiki 1.23, tracking categories are listed in the $wgTrackingCategories configuration variable, and can be viewed on [[<tvar|2>Special:TrackingCategories]]. Since MediaWiki 1.25, tracking categories, which are added by MediaWiki itself, are hard-coded in the MediaWiki source code, and $wgTrackingCategories is kept for backwards compatibility.

What category to use is determined by the tracking category's system message, that is, a page in MediaWiki namespace. If the message is a single dash (-), then the tracking category is disabled. Often wiki admins mark such categories as hidden (using the (<tvar|2>__HIDDENCAT__ magic word), since they are meant for maintenance and not general consumption. Some sites use [[<tvar|3>Extension:ParserFunctions|Parser functions]] to modify which category is used based on namespace, but that doesn't work properly until 1.19.

Default category	Message	What triggers the category's inclusion	Version
Pages with too many expensive parser function calls	expensive-parserfunction-category	The page uses too many expensive parser functions (like `#ifexist`). See Manual:$wgExpensiveParserFunctionLimit.	<tvar\|rev>1.13 Before that, ParserFunction extension used pfunc_max_ifexist_category
Pages containing omitted template arguments	post-expand-template-argument-category	The page is bigger than `$wgMaxArticleSize` after expanding a template argument (something in triple braces, like `{{{Foo}}}`).	1.13
Pages where template include size is exceeded	post-expand-template-inclusion-category	The page size is bigger than `$wgMaxArticleSize` after expanding all the templates, so some templates were not expanded.	1.13
Noindexed pages	noindex-category	The page is not indexed by robots because it has the magic word `__NOINDEX__` on it and is in a namespace where that flag is allowed.	1.15
Indexed pages	index-category	The page has a `__INDEX__` on it (and is in a namespace where that flag is allowed), and hence is indexed by robots where it normally wouldn't be.	1.15
Hidden categories	hidden-category-category	The category contains `__HIDDENCAT__` in its page content, which prevents it from showing up in the category links box on pages by default.	1.13
Pages with broken file links	broken-file-category	The page contains a broken file link (a link to embed a file when the file does not exist). This does not include links to files on the bad image list, files that cannot be displayed inline (due to lack of handler support), links directly to a file page (by preceding with a colon, aka `[[:File:Example.png]]`). The category, if enabled, is linked from Special:Wantedfiles since 1.19.	1.18
MediaWiki:Syntaxhighlight-error-category	syntaxhighlight-error-category	MediaWiki:Syntaxhighlight-error-category-desc The SyntaxHighlight extension bundled with MediaWiki adds this.	1.26

Extensions can also add new tracking categories (via Parser::addTrackingCategory method).

Some wikis add other sort of tracking categories via some hacks, for instance [[<tvar|itwiki1>w:it:Categoria:Pagine con errori nelle espressioni|this category]], which tracks pages with <tvar|expr>#expr errors, added through the [[<tvar|itwiki2>w:it:Special:PrefixIndex/MediaWiki:Pfunc expr|relevant errors]] shown on such pages.

This page was moved from mw:Help:Tracking categories. It's edit history can be viewed at Help:Tracking categories/edithistory