That's quite an undertaking! (On my system, there's 196478 files on my / and /boot partitions.)
You might want to have a look at 'rpm -ql' and 'rpm -qi'.
rpm -ql mozilla <- will list all the files in the mozilla package
rpm -qi mozilla <- will give some information on the purpose of the mozilla package
You can get a list of all the installed packages with 'rpm -qa'.
is supposed to be the Linux filesystem standard, but most distributions don't stick to it too well. It might prove useful, though.
None of this will tell you what each individual file is for, but once you know the package a file came from, Google may be able to provide the answer.