I heard it through the grapevine that the Library of Congress is accepting bids to become their #WebArchiving vendor. The documents provide a little window in on some of the details of how they currently do web archiving (transferring Bagit packages from S3) and the reports they generate to monitor it.
https://sam.gov/workspace/contract/opp/a2c5551af2b74c3d84c775032c83a55e/view