From Jimbojw.com

Version 0.1 of the RawMsg Extension has been released and is available for download. It adds a parser function called #rawmsg for inserting bits of raw HTML into wiki pages.

The RawMsg parser function expects to be called in the following way:

{{#rawmsg:message-name}}

Where message-name is the name of the message to inject.

For example, calling {{#rawmsg:test-pattern}} would grab the content of [[MediaWiki:rawmsg-test-pattern]] and insert the content directly into the page.

The MediaWiki namespace was chosen to house the HTML fragments so that only Sysops may edit them due to the XSS risk. Also, the messages must begin with 'rawmsg-' to decrease the likelihood that an obscure accidental MediaWiki article could be used as an XSS attack vector.

Enjoy! As always, I'll be happy to answer any questions.