Might be more of a ELI12, but here goes: There are people that like to write pictures into the Bitcoin blockchain. Some Bitcoiners don’t want pictures in the blockchain. They want that only payment transactions can be written to the blockchain. The Knots marketing team has been telling them that running Knots makes it harder to put pictures in the blockchain, because Knots does not forward unconfirmed transactions with pictures.

In the past two years, picture-lovers have spent hundreds of millions of dollars to put pictures into the blockchain. Bitcoin Core contributors also don’t like picture transactions, but they think that just not forwarding transactions will not slow down picture transactions. Instead it will make picture enthusiasts build tools to give picture transactions directly to miners. The Bitcoin Core contributors worry that if picture-lovers give their transactions directly to miners, this will a) slow down block propagation, b) disimprove fee estimation, and c) disproportionally benefit the largest miners. Picture transactions can only be effectively forbidden by new consensus rules that reduce the programmability of Bitcoin transactions, but Bitcoin Core contributors think that working on that would take too much time and effort, and that neutering Bitcoin’s scripting system to prevent picture transactions is too high of a price. Many Bitcoin Core contributors think that picture transactions will be too expensive in the long run and will be naturally priced out by more valuable payment transactions. They say that is unnecessary to make the network work worse or to reduce Bitcoin’s programmability to fight against picture transactions. This makes the people angry that want Bitcoin to only be used for payment transactions. They want that Bitcoin Core contributors do everything they can to fight picture transactions.

Last week someone pointed out that someone intends to write data into payment outputs. This is especially bad, because unspendable payment outputs are stored in the UTXO set and have to be kept by all full nodes forever. They bring up the idea to allow bigger OP_RETURN outputs, because OP_RETURN outputs cost a little less than writing to payment outputs and are not stored in the UTXO set. They note that the picture writing happens mostly in witness data which is already cheaper, and therefore probably only any data written in payment outputs would be written to OP_RETURN outputs instead. A participant of this conversation opens a pull request to Bitcoin Core to propose dropping the OP_RETURN limit and removing the configuration option to set a limit. The Knots marketing team uses this proposed code change as an opportunity to stoke fear by saying that Bitcoin Core has already decided to do this, and that this code change would bloat the blockchain, the UTXO set, the mempool, make validation slower, invite even more picture transactions, and spell the end for payment transactions. They also admonish that Bitcoin Core is silencing people who don’t like pictures by dropping the configuration option. However, it is just a proposal that is being discussed at this point. Further, OP_RETURNs appears in output scripts, and output scripts are not subject to the witness discount. So, OP_RETURN data pays the full price for blockspace, more OP_RETURN data results in smaller blocks, and OP_RETURNs are cheap to validate. Before any Bitcoin Core contributors realize what was happening, picture-haters start demonstrating in Bitcoin Core’s workplace. When some of the demonstrators get carried away, security asks them to leave. The Knots marketing team decries censorship to further fan the flames. Meanwhile, many Bitcoin Core contributors think that mining centralization is an important issue and that writing to the UTXO set is much worse than potentially a few additional OP_RETURN outputs, and they are divided on whether they configuration option should be kept or dropped. Another proposal is created that only changes the OP_RETURN limit but keeps the configuration option. A bunch of Bitcoin Core contributors then spends a week to explain the broader picture and their perspective instead of working on the things they were going to do otherwise.