It's not just Chinese labs that do this, lots of companies upload a README to a GitHub repository then link that repository from the website, I guess so they can have a GitHub icon somewhere on the website?
Submission is basically a form for requesting access to their closed API (which ironically is called "OpenPlatform" for some reason).
Same thing in English, you have huge enterprises which basically operate on the complete opposite end of the spectrum, and end up calling themselves things like "OpenAI".
It even bleeds into marketing pages, go to the Llama website and you see "open source model" plastered all over the place, completely misusing both the "open" and "source" parts of it.
Submission is basically a form for requesting access to their closed API (which ironically is called "OpenPlatform" for some reason).