ParserFunctions - Mediawiki
From Help Wiki
Information on the extension ParserFunctions.
The MediaWiki extension ParserFunctions is a collection of parser functions (note the difference between the name of the collection, and the general term). These parser functions have a hash character in front of the function name, so they typically have the syntax:
{{ #functionname: argument 1 | argument 2 | argument 3...}}
See https://www.mediawiki.org/wiki/Help:Extension:ParserFunctions for a complete description of functionality and syntax.
Example:
{{ #time: "The month is" F }} → The month is November