This wiki supports InterWiki links in a style copied from 
UseMod:
wiki. Links to pages in other wikis can be made without having to know
or type the full URLs, for example: MeatBall:InterWiki will link to
the page named "InterWiki" at Meatball wiki.
The InterWiki map is taken from the the <verbatim> block in
InterWikiMap, but that page must be locked for it to work. This denies
a potential hacker the ability to nefariously change every InterWiki
link to point to some evil URL. If no map is found in InterWikiMap (or
the page is not locked), PhpWiki will fall back to using the file
lib/interwiki.map in your phpwiki distribution. The InterWiki map
file in use at PhpWiki: can be viewed at
http://phpwiki.sf.net/interwiki.map.
The map file is manually updated. It is based upon and periodically
synchronized with UseMod's InterMap
but it is not quite identical. One notable difference from UseMod:
is that PhpWiki supports '%s' within the URLs in the map--see the
entry for RFC for an example of how this works.
Not all of the entries in the InterWikiMap are actual wikis. For
example, these are just regular web sites: Dictionary:fungible,
JargonFile:Alderson loop, IMDB:Roman Holiday, RFC:2822, and
ISBN:020171499X.
The "Category" moniker is a special entry which allows one to link a
wiki page to a Category page without creating a back-reference. Thus
Category:Category links to the CategoryCategory page, yet this page
won't show up in the back-links listing of CategoryCategory.
The term "InterWiki" also refers to a broader concept. See
PhpWiki:InterWikiSearch for more links.