Discovering Functions or Who Called What
 

My first question for anyone in the know is this....

How are all of the functions posted at http://www.wowwiki.com/ discovered?

I am having a few problems with a mod of mine and the problems arise from something being called on GameTooltip, but after hooking every single known function to it, no 'known' functions are being called on it to produce this unwanted behavior.

I've seen some advanced addons where they will invasively hook into functions to get at stats, but I'm not sure if I can do that if the functions are not created by an addon.

Is there a way for me to find out what is being called on GameTooltip to break my mod? Any help you guys have would be very much appreciated.