The Controversy: OP_RETURN Unleashed In June 2025 Bitcoin Core merged a pull request that effectively removes the OP_RETURN size cap. The move has reignited a long-smouldering debate: is storing JPG images on-chain “spam,” and should Core developers stop it? Roughly 17 % of reachable nodes now run Bitcoin Knots, a client that ships extra spam filters. Core maintainers counter that the fee market—not protocol limits—remains the only sustainable defence.An Information-Theoretic Reality Check Cl...

The Controversy: OP_RETURN Unleashed In June 2025 Bitcoin Core merged a pull request that effectively removes the OP_RETURN size cap. The move has reignited a long-smouldering debate: is storing JPG images on-chain “spam,” and should Core developers stop it? Roughly 17 % of reachable nodes now run Bitcoin Knots, a client that ships extra spam filters. Core maintainers counter that the fee market—not protocol limits—remains the only sustainable defence.An Information-Theoretic Reality Check Cl...