Over in pgsql-hackers, I've proposed removing the db_user_namespace parameter in v17 [0]. I am personally not aware of anyone using this parameter, but I wanted to give folks an opportunity to object in case they are using it (or are aware of someone who is).
[0] https://postgr.es/m/20230630200509.GA2830328%40nathanxps13 -- Nathan Bossart Amazon Web Services: https://aws.amazon.com
