It’s actually pretty simple. Back in 2023, spammers figured out how to bypass the datacarriersize filter in Core. That loophole made it easier to deploy ordinals and inscriptions by injecting arbitrary data into what appeared to be legitimate monetary transactions.

Some users raised the issue and submitted a PR to Core to patch the bug and stop the abuse of nodes. Core shut it down, calling it “controversial.” Later, someone discovered that Core had already realized datacarriersize wasn’t functioning properly and quietly edited the filter’s description to retroactively justify not fixing it.

When they got called out on it, one of the maintainers even claimed that changing the description counts as a valid way to fix a bug. That vulnerability is still present in earlier versions of Core and you can’t simply make it work.