Now what is it exactly? Basically the app scans through a folder you drop over it and outputs a HTML report of each and every file/folder inside. Now it not only shows all the files, it scans all php files for functions and classes and shows you where exactly those are (with line numbers), so you get a detailed overview of the scripts functions and classes. The HTML output is CSS formatted, so it shouldn't be too hard to skin it for your very own needs. Additionally the app generates some stats of the whole package, an example:
10 folders, 163 files, 1101512 bytes (total), 1022055 bytes (scripts), 125 php files, 50 php files with functions, 30881 lines of code, 786 functions and 25 classes.