These should be reported to upstream http://qbnz.com/highlighter/ and ask here to update the version of bundled geshi once fixed.

Although it's upstream, we can simply fix it ourselves.

Besides the demo on the site hilites correctly, so it obviously has already been fixed in some newer version we don't use yet.

There is no html5.php file in GeSHi standard distribution.

Furthermore, their bugtracker isn't available for the moment: http://geshi.org/developers/bugs/

Thank you for your report.

Code review: https://gerrit.wikimedia.org/r/#/c/10286/

Danny B., please read http://www.mediawiki.org/wiki/Developer_access if you wish to join the MediaWiki development community and be able to add yourself patches in our code review queue.

You can get an overview of the process on http://www.mediawiki.org/wiki/Git/Workflow

I used the following commands to put your patch in our community code review site:

git clone ssh://review/mediawiki/extensions/SyntaxHighlight_GeSHi.git
cd SyntaxHighlight_GeSHi
git checkout -b geshi-37044
(editing the relevant file)
git add geshi/geshi/html5.php
git commit -a -m "(bug 37044) Fixed HTML5 syntax highlight typo"
git review

• merged gerrit 10286.
• Removed upstream tag. That should only be added once an upstream bug id is known. See https://bugzilla.wikimedia.org/describekeywords.cgi#upstream.

Even though geshi library is now physically bundled in the repo, we shouldn't be making changes to it.

Okay,

I've made further inquiries.

There is two versions of GeSHI:

• 1.0, with the HTML5.php file
• 1.1, currently in development

The correct one is the 1.0.X, as indicated in extension README file.
http://geshi.svn.sourceforge.net/viewvc/geshi/trunk/geshi-1.0.X/

The typo reported by Danny B. have been fixed 8 months ago:
http://geshi.svn.sourceforge.net/viewvc/geshi/trunk/geshi-1.0.X/src/geshi/html5.php?r1=2430&r2=2479

The GeSHI project doesn't seem very active currently.

I opened the bug #37585 to track the upcoming release and fix it.