Relax OP_RETURN standardness restrictions

The discussion between Vojtěch Strnad and Antoine Poinsot on the Bitcoin Development Mailing List touches upon the optimization of blockchain transactions, specifically focusing on how to efficiently publish transactions within the Bitcoin network. Their conversation reveals an interest in adapting transaction publishing to a method that utilizes SIGHASH_SINGLE|ACP transactions, where each output would consist of a 144-byte OP_RETURN. This approach is suggested as a means to batch publish transactions, potentially offering a more efficient use of blockchain space.

The idea of moving towards this method stems from the desire to avoid revisiting efficiency improvements in the future, indicating a forward-thinking approach to blockchain transaction management. The dialogue acknowledges a potential drawback in adopting this method: the reservation of multi-output transactions for some form of signaling mechanism, which was previously not possible due to limitations in Bitcoin Core's relay capabilities. Despite this concern, additional OP_RETURNs are viewed as a costly signal, implying that the benefits of the proposed adaptation might outweigh the disadvantages.

This exchange highlights the ongoing efforts among developers to enhance the operational efficiency of the Bitcoin blockchain. It reflects a proactive stance in addressing scalability and optimization challenges, underscoring the importance of continuous innovation in the cryptocurrency domain.