There is no one file you can send. Riot does very in-depth analysis before firing off a third-party accusation, so something on your computer, intentionally or otherwise, is likely interfering with or attempting to access League's code.
Your best bet would be to send a ticket to Riot Support to see if you can get more information, but realistically all that is likely to do is cause them to recheck their data to confirm that the ban is not in error. Riot does not reveal what or how they detect third party usage, as that means those people making the programs can find out what Riot is looking for and avoid it.