But BIP 174 was merged like two years. It's about PSBT. There are a bunch of RPC commands to make PSBTs and all. For a reader interested in informing himself on what BIPs made it to the bitcoin core code, they would just ignore BIP 174. Even if there are some details that are left to be implemented, there should be a status like "Partially merged" or some indication that the BIP as made it into the codebase.