Where is firefox about:config reference?

To add useful reference to firefox book, I was seeking web sites. But unfortunately, I could not find it.

Instead of it, mozilla reference was found. Most of the description could be fit to firefox, but not all. And the worse, I found this reference was not under maintenance.

http://kb.mozillazine.org/Firefox_:_FAQs_:_About:config_Entries

One of the most serious problems for open source project is documentation.