I expect they're using the moderation filter (https://platform.openai.com/docs/guides/moderation/overview), but calling it in parallel to the generation so that it doesn't add latency to the response.
(the actual content is quasiobfuscated as it comes as a respond to the initial websocket request or something along those lines, makes the useful information harder to dump (thank you EU for the data export workaround), but they certainly like that you see those moderation checks every time it says anything. an always-on panopticon)
(And 'they' here might mean the company as an abstract entity, or perhaps just the engineer put in charge of implementing this feature?)
There's a browser plugin called DeMod or something that disables it but I don't know how well it works.
But realistically they could mod forcibly on their end if they really wanted to, only issue is API use may run into issues where a legitimate use ends up getting stomped by moderation.
That's why it's honestly just better for them to make moderation optional, they should have a button for it in CGPT interface just as Google has "safesearch on/off".
Because of the way it works they can fundamentally not prevent it from producing explicit, violent or adversarial output when someone is focussed on getting it to do so without removing the very magic that makes it so good for everything else. So they should stop trying already, like damn.