Among my many tasks with Phex, one is to create simple source code matrix.
Just a text or html document (in tree format) that lists all source files and what they do.
Also included would be showing which sources import or extend other sourses and which ones are included in different packages.

The more you are exposed to Phex code the less important something like this is. But for new devs (to Phex and Java) it could be very useful for digging in.