For the vast majority of the games it doesn't really matter, the file will do its job. Just make sure to use a name that corresponds to its function so it's clear to you. I'd also avoid using spaces in the filename, like incest patch.rpa
, even though I just tested it with Savior and it works even like that.
Edit: though, to be fair, some games do use a function to see if a certain file exists in the game directory to enable extra content and such.