As for the good old “OpenAI is not open” complaints, you can use my ClosedAI extension which follows the footsteps of CloudToButt https://github.com/clopen/ClosedAI.
Since reading code is significantly harder than writing code, I hope OpenAI's model allows users to infer a natural language explanation of a given snippet of code. This should be possible if it is a generative model.
If you google "OpenAI codex" the following description comes up, "OpenAI Codex translates natural language to code, as first seen in GitHub Copilot. Latest. Introducing Triton: Open-Source GPU". Though this appears to be missing from the actual page.