[_ck_]

It sends all the invisible code before the webpage that your browser requires to understand the language, etc.

In theory commenting it out is very bad but for some reason with bb-gzip it’s being triggered twice which should not happen and is bad. The fix I gave you is a lazy workaround for now until I have time to address it properly one day (and might need a completely different fix with bbPress 1.0.1 etc)