Template:Purge/doc

undefined produces a link that will clear the cache and rebuild page from the wikitext.

Purpose
For efficiency in service, MediaWiki caches pages. Depending on the exact sequence of actions editors follow, one may view an out-of-date version of a given page. This happens most often on heavily-edited pages and on pages which contain an instance of transclusion.

purge adds to any page a link that, when clicked, not only reloads the page, but clears the server cache, forcing the page to be completely rendered "from scratch". This is not a one-time solution; generally, editing a page is itself sufficient to purge cache. Rather, it is a measure taken in anticipation of the frequent need to purge.