It’s not the same as the paper for performance reasons. This is noted in the github README. Martin said on Software Engineering Daily late last year that Automerge was three orders of magnitude faster than his published version of the JSON CRDT.

This is my second time highly recommending a Software Engineering Daily podcast with Martin Kleppman on it. He is really smart and able to break down really complex topics in a way that's easy to understand. If you've never heard of CRDTs before, have a listen - https://softwareengineeringdaily.com/2017/12/08/decentralize...