unknown module in my server to get PHP errors in HTML tables

Sorry to ask this... I manage Apache and PHP in my computer. But having installed a lot of things, I've lost track of some of them. (Things I find really useful to have at my job, or to restore in case of emergency).

The problem is that I have installed this thing which displays PHP errors in a nice and colored html table, but can't remember what I have installed or configured to get it work like it.

Can you give me a hint about it?

I'm using Debian Lenny, Apache 2.2 and PHP 5.2

Here's a screenshot:
_{(source: linuxquestions.org)}

Thank you very much for reading. Javier