Only required for encrypted formats. If you use decrypted formats like .wua or "Loadiine" (folders with code, content, and meta), you don’t need a keys.txt at all. Where to Put It:
The short answer is CEMU is an emulator that focuses on high-level hardware simulation, not on breaking encryption. The developers have intentionally avoided baking generic keys into the emulator to maintain a clear legal position: CEMU itself contains no copyrighted code or keys. The user must provide them.
A typical keys.txt file contains entries like this: