From the author Connor Leahy:

Hey OpenAI, I’ve replicated GPT2-1.5B in full and plan on releasing it to the public on July 1st. I sent you an email with the model. For my reasoning why, please read my post:

https://medium.com/@NPCollapse/gpt2-counting-consciousness-and-the-curious-hacker-323c6639a3a8

Excerpt from post:

TL;DR: I’m a student that replicated OpenAI’s GPT2–1.5B. I plan on releasing it on the 1st of July. Before criticizing my decision to do so, please read my arguments below. If you still think I’m wrong, contact me on Twitter @NPCollapse or by email (thecurioushacker@outlook.com) and convince me. For code and technical details, see this post.