PlanetOZH writes :
Whenever I start hacking a bit my Wordpress installation, I always end up asking â€œin what file is this __ function located ?â€ and have to search /wp-include directory using grep to find it. So, to make such a search easier, I gathered the full list of functions used in WordPress 1.2 â€“ and their default arguments.
If you have been in a similar situation before, worry not! You can use the excellent PHPXref installs that can be used to search for functions, variables, classes and such in WordPress code.
Don’t miss the “search” tool/form that’s present in the top right corner, in the black horizontal bar. Also, when you are browsing code, clicking on a function name will take to the page showing where the function is defined and all the places it is used in.
Now you know why support volunteers seem to know where each function is, and what they do