Probably Ilya and his team. The recent discovery was made by him and his team.
"The technical breakthrough, spearheaded by OpenAI chief scientist Ilya Sutskever"
I think he is referring to an AGI that is 10000x more productive than a median programmer
What I took from that comment was that people at open AI were successfully making tools that led to a 10,000 fold increase
GPT4. Everyone uses it to do software engineering now and the people who developed it are responsible for that.