[_5hxt]

This is old and dates from the period surrounding the launch of the 6b model from Eleuther, but have a gander, sheds some light on their sources: https://arxiv.org/abs/2101.00027

GPT4 technical paper doesn't seem to disclose it (or I didn't dive deep enough): https://arxiv.org/abs/2303.08774

One could ask it niche questions about the stuff you mentioned to gain insight, but may stem from discussions about it.