Relax OP_RETURN standardness restrictions

The discussion highlights a positive stance towards relaxing OP_RETURN standardness restrictions within the Bitcoin protocol, suggesting that such a move could foster broader utility and innovation. Key references are provided to deepen understanding, including proposals and discussions on GitHub related to these changes (Peter Todd's proposal and an issue discussion on ordinals GitHub issue). The conversation touches on the technical implications of implementing a -datacarrierenum flag, which would allow for a more nuanced control over OP_RETURN outputs by nodes running Bitcoin full-node software. This flexibility could enhance applications like custom block explorers but also raises concerns about potential denial-of-service (DoS) vulnerabilities, especially in scenarios where callbacks are executed prematurely for latency benefits.

The email delves into the complexities and potential downsides of loosening OP_RETURN restrictions. One significant concern is the possibility that the value of a single transaction output, termed as "exogeneous" value, could surpass the block reward, leading to economic imbalances and security risks such as double-spend attacks in specific reorganization scenarios. This scenario is particularly troubling in the context of assets with high value, such as those seen in ordinal markets during halving events, where assets linked to coinbase public keys have garnered substantial prices.

Despite these challenges, the current landscape of multi-party transactions and contracting protocols, like coinjoins and lightning networks, remains unaffected. These systems inherently rely on the exchange of coins or committed fees to settle off-chain states, thereby maintaining the integrity and linearity of blockchain progression. The correspondence concludes by implicitly encouraging further examination and discussion of these topics within the development community, without offering a definitive solution to the highlighted concerns.