Looks fine to me.

It starts about in the middle of the file and syntax coloring must be enabled.

Ah, I see it now.

I guess this is caused by the heredoc being hidden as common lines.

It's not about being hidden. It's just getting confused at the heredoc.

I filed this bug upstream almost 3 weeks ago. Resolving LATER until something happens there.

Seems to be upstream of Gerrit as well, see http://code.google.com/p/google-code-prettify/issues/detail?id=41

Switching from LATER to the second most relevant resolution for fear of information loss. http://article.gmane.org/gmane.science.linguistics.wikipedia.technical/65116

Both upstream and up-upstream bugs are still open; I can't actually see the bug myself but it's probably me.

Cannot spot anything strange in https://gerrit.wikimedia.org/r/#/c/15451/1/Babel.class.php either.
<<< (heredoc) is used in lines 95 and 233 but nothing weird visible.

Nikkerabit: Do you remember what the problem was? (Screenshots welcome.)

Created attachment 11809
Example from URL

As I said it was just me. :) Seen on Firefox and Chrome, as explained on https://code.google.com/p/support/issues/detail?id=3763 : after $box = <<<EOT (and actually even starting a bit before it), everything is treated as a single string so all colours get lost; compare for instance the lines selected in the screenshot.

Attached: