BIP110 supporters are saying that Core blew open OP_RETURN. They didn't. They just removed a sign. Bitcoin's real OP_RETURN limit isn't 83 bytes or even 100KB. Those are policy. You can think of them as speed-limit signs each node chooses to post. The real limit is ~1MB. That's the law of nature, or consensus rules. Think of it as the speed of light, 299,792,458 m/s. A fixed constant. No dev, no miner, no config flag moves it. OP_RETURN data is non-witness data, 4 weight units per byte. Fill a whole block with it: 4,000,000 ÷ 4 = ~1,000,000 bytes. That's the real limit. It was the limit before v30 too. This means the 83-byte cap was never Bitcoin's limit. It was a sign posted in front of a road that was always ~1MB wide. And miners were already driving past it, accepting big non-standard transactions directly, bypassing the mempool entirely. All v30 did was take the sign down. Default datacarrier size went from 83 to 100,000 bytes. Should they have taken the sign down? That's debatable, but it also isn't relevant (outside of angering some people). However, there were zero consensus changes. Not a soft-fork. Not a hard-fork. The set of valid blocks is identical before and after. So when someone says "Core changed Bitcoin," ask them: which consensus rule changed?