2. This is a requirement for companies registered in the UK. You should also read your own link, it doesn't say anything about the company's presence on 3rd party websites.

3. This is such a remote reason it's laughable, there are plenty more things that are more relevant to potential job applications, such as whether they are hiring at all or not.

You just want them to mention it because it's a Chinese company. If they were American, Mexican, German or Zimbabwean you wouldn't give the slightest fuck.

Where do you see that? e.g. I just checked https://openai.com/about/ and it doesn't say where they are based. I have no associations either way, but I usually have to work hard to find out where startups are based.

I can't say I remember any model/weights release including the nation where the authors happen to live or where the company is registered. Usually they include some details about what languages they've included to train on, and disclose some of their relationships, which you could use for inferring that from.

But is it really a convention to include the nation the company happen to be registered in, or where the authors live, in submitted papers? I think that'd stick out more to me, than a paper missing such a detail.