It was them. https://openai.com/research/openai-five
They've since abandoned all their reinforcement learning projects. (aside from RLHF for training ChatGPT)
They've since abandoned all their reinforcement learning projects. (aside from RLHF for training ChatGPT)
That's a shame, I was really impressed with their research in that space.
That was the same time they depreciated OpenAI Gym: https://github.com/openai/gym