Remote attestation is just generating a random blob on the remote side and then making the tpm 2.0 module on a computer sign the blob with a private key. You then provide the signature and the public key to the remote for verification. That enrolls that device. After that you can "verify" with a new binary blob and validate a new signature came back with the same key. That full loop is remote attestation. The idea is your disk didn't get moved to another computer. It's a security thing that Linux does need and is capable of being fully open source.

It has nothing to do with drm.