Sorry, that's nondescript. XHTML/CSS syntax coloring to display Perl code. I've done it with Syntax::Highlight::Perl -- did a very buggy version with perltidy once -- in the past and PPI in the last year or so.
I know that Jonathan Rockway's Angerwhale does generic syntax coloring of many different languages (it's based on a package, the name of which eludes me right now). I keep meaning to look into it.