Murch, developer of Bitcoin Core and editor of the official Network Improvement Proposal (BIP) repository, published on-chain data showing that OP_RETURN outputs larger than 83 bytes represent just 0.0032% of Bitcoin’s total block space.
In his book, he called this percentage “shocking” in response to those warning that Bitcoin Core v.30 opens the door to potentially illegal content. spam Enabling these types of outputs allows them to be used within the Bitcoin network.
The data comes from two Dune Analytics graphs created by Murch himself and covers the period February 2023 to May 2026. The first graph records the weekly number of OP_RETURN outputs sorted by size. In the week analyzed by March, Output greater than 83 bytes represents only 0.000075% of the total output.
The second graph measures the total space occupied by these outputs in bytes per week. Anything larger than 83 bytes will absorb 0.14% of the total space consumed by OP_RETURN output. Equivalent to 0.0032% of Bitcoin block space.
Both graphs published by the developer show a small amount of OP_RETURN output that exceeds the 83-byte limit for network usage.
Contrary to data provided by March, a report released by Bitcoin Node brokers in mid-April warned that registrations via protocols such as Ordinals and Runes and transactions with OP_RETURN accounted for 44% of Bitcoin operations during the last quarter. Of this percentage, almost 63% were OP_RETURN outputs.
This data is consistent with that reported by CriptoNoticias in October 2025, but reflects a significant increase in the rate shown by Murch when considering only OP_RETURN operations larger than 83 bytes.
OP_RETURN is a Bitcoin opcode that allows you to include arbitrary data (text, identifiers, records) within a transaction. Until Bitcoin Core 29, that data limit was 83 bytes.
In October 2025, after discussions that began several months ago, Bitcoin Core 30 default limit of 100,000 bytes has been expandedThis change has been criticized by the Bitcoiner community. The reason is that, according to its critics, this change will promote the use of Bitcoin as a file network and give the Bitcoiner community more to consider. spam By occupying block space without transferring monetary value.
Same data, opposite arguments
Blockstream co-founder Adam Back ironically dismissed the alarm. In X, he writes that Bitcoin Mechanic (a developer and one of the most vocal critics of the changes introduced in Core 30): “Definitely worth forking over.”is a satirical take on the position of Mechanic and others who propose introducing soft forks as proposed by BIP-110 in order to avoid the inclusion of arbitrary data in Bitcoin. For Buck, this proposal is disproportionate to the impact that the data do not support.
One miner and node operator pointed out, “So why was it so important to have it open by default in the reference implementation?” and warned that if there were very few uses of OP_RETURN output larger than 83 bytes, the expansion in Core v.30 would not have been necessary.
Similarly, another user responded with the same logic. “The problem is quality, not quantity,” he said, arguing that the current low incidence does not justify opening up the limit and that the problem is not the number of outputs that exceed 83 bytes today. But what kind of content will we be able to embed without limit tomorrow?
Steve Tippeconnic, a developer specializing in quantum, added a more precise technical critique. According to him, expanding the limits on OP_RETURN did not solve the problems that its defenders claim. witnessa transactional space where digital signatures are stored and where protocols such as Ordinals can also embed information.
On the other hand, a quantum expert said: This change opens new vectors for embedding data more directly and visually.without touching the root of the argument. “This is exactly what everyone at BIP-110 predicted,” he wrote, linking the results to the caveats the proposal raised before Core 30 was released.
BIP-110: Suggestion to revert changes
BIP-110 is a soft fork proposal created by anonymous developer Dathon Ohm that aims to limit non-financial uses of Bitcoin block space and reserve it for payments and settlements. As reported by CriptoNoticias, this proposal was included by default in the latest update of the Bitcoin Knots client, a software that filters operations enabled in Core v.30.
To activate BIP-110, A critical mass of node operators voluntarily installs that client to produce the desired effect. If this adoption does not occur, the BIP-110 rule will never go into effect. Because if there aren’t enough nodes to reject blocks containing arbitrary data, the network will simply continue accepting blocks as before.
In that context, March’s data reignited the debate over whether the expanded OP_RETURN limit represents a real risk to Bitcoin or a disproportionate warning.
(Tag translation) Bitcoin (BTC)
