Manual:Hooks/TitleSquidURLs

Details
This provides more fine-grained control over purging of pages cached by an HTTP accelerator such Varnish or Squid. Normally, when the cache is purged, the internal URL is purged, as well as the  variant of that. This allows a hook listener to change (usually, add to), the list of affected URLs, if additional URLs depend on the content of a title.