GeezerVison

Warning: This extension is still work in progress, and escaping is not fully tested yet and not
implemented in all contexts (E.g. for CSS).

This extension allows wiki administrators to make small snippets of raw html, that oridinary users
can include on pages. The snippets can take parameters like normal templates, which should be
contextually escaped.

This is very similar to the popular Widgets mediawiki extension. The main difference is instead
of using the Smarty templating language, it uses MediaWiki inspired template parameters with
context-sensitive escaping. It is the author's opinion that Smarty has too many hidden gotchas
to be used safely by non-technical users, often resulting in XSS. It is hoped this will be a safer
option. It should be emphasized however that any form of raw html is dangerous and should be used carefully.

To install this extension, simply add wfLoadExtension( 'HTMLTemplates' ); to your LocalSettings.php.

After that, people in the editinterface group should be able to add templates in the HTMLTemplate namespace.
You should be able to include them like normal templates, with parameters just working and automatically
being escaped.