I don’t understand what goes on during “sector sealing.” The most detailed explanation I can find is in the spec, § 2.6.2 (requires local copy), which basically explains the sealing process as assembling the raw data that is to be stored into a Merkle tree and generating a proof. Proof of what? Knowledge of the tree root hash?
Also, the uppercase term SEAL is sometimes used. Is SEAL an abbreviation for something?