Bitcoin Core reverses the plan to remove the OP_RETURN limit in version 30.

Bitcoin Core developers reversed their plan to remove user control over the default data size of OP_RETURN just before the issuance of Core version 30. Pull request 33453, merged by maintainer Ava Chow, allows users to continue adjusting the data size limit of OP_RETURN as they wish.

This change is a small victory for Knot node operators, who believe that most of the node's mempool should reject transactions containing large, irrelevant data not related to the transfer of bitcoin. The goal is to avoid the burden of storing or transmitting arbitrary data.

Core v30 still increases the default size of OP_RETURN from under 90 bytes to 100KB, but users can override this limit. The removal of the configuration option has been indefinitely postponed. While this reversal maintains user customization rights, the controversial changes from v29 to v30 remain in effect.