'''WLH''' (WhatLinksHere) and the search parameter '''linksto'" track (index) URL-style internal wikilinks such that the most efficient way to list all wikilinks to a given fullpagename takes up to eighteen searches for them alone:
# `insource: "canonicalurl:namespace:pagename"`
# `insource: "canonicalurl:namespace_alias _1:pagename"`
# `insource: "canonicalurl:namespace_alias _2:pagename"`
# `insource: "canonicalurl namespace:pagename"`
# `insource: "canonicalurl namespace_alias _1:pagename"`
# `insource: "canonicalurl namespace_alias _2:pagename"`
# `insource: "fulurl:namespace:pagename"`
# `insource: "fulurl:namespace_alias _1:pagename"`
# `insource: "fulurl:namespace_alias _2:pagename"`
# `insource: "fulurl namespace:pagename"`
# `insource: "fulurl namespace_alias _1:pagename"`
# `insource: "fulurl namespace_alias _2:pagename"`
# `insource: "fulurl:namespace:pagename"`
# `insource: "server localurl:namespace:pagename"`
# `insource: "server localurl namespace:pagename"`
# `insource: "server wiki namespace:pagename"`
# `insource:"https SERVER wiki namespace:pagename"`
# `insource:"https SERVER localurl:namespace:pagename"`
* These many searches don't prove a link — `[{{fullurl:...]` or `https:{{SERVER}}` or `canonicalur:{{SERVER}}` — but are the best "probable links" to a page, or best "pattern to investigate".
* These many searches don't include the possibility of `{{anchorencode}}` and `{{urlencode}}`. And the parameterized calls that fullurl, canonicalurl, urlencode can make.
* Linksearch and its MediaWiki extension are obsoleted. But now we have CirrusSearch and linksto.
OK, but still, why so many searches?
* Indexed CirrusSearch searches make `canonicalurl:namespace:pagename` atomic. With that term indexed, you can't find canonicalurl or namespace or pagename. You can only find canonicalurl:namespace:pagename. The same is true for fullurl, and for namespace:pagename.
* The URL-style internal wikilinks take any namespace alias, for example WP, project, or Wikipedia, all of which would apply in a search for internal wikilinks to a project page.
* The URL-style internal wikilinks will take a space after the parser function name.
* Insource doesn't take OR.
* Regex has no filter to accompany it for this instance. Name one. Linksto cannot be used for a filter for regex because linksto does not recognize URL-style links.
On a happier note linksto reports every kind of namespace in one search, yeah! And WHL reports every kind of link in every way to ''the content'' of a page ''not just a name of a page''. Happy searching!