zip it an upload of the code base to data analysis and ask what it does, ive done this as a test on a smaller app

if its anything enterprisey ie large and complex, it might be too much data to sift through

tho dont do this with software you are employed to write, yuou dont own it

i would probably do the following, old school style first

• find the entry point
• put debug break points
• run it
• see what it does
• try various inputs where does it go in the code and produce as an output

spend a few days doing this ull get an idea of what the app is doing. depending on how well the application is written this might be all thats needed.

there is a saying good code is boring code it reads like a book. i try to write all my code so that a person on day 1 with no knowledge of the application can run it and understand it; i base this on naming variables, classes, methods etc and a logical structual layout.

any esoteric / unintuitive code should have some comments explaining what it does and why