OAKLAND, Calif. — OpenAI’s president Greg Brockman got grilled by Elon Musk’s lawyer on Monday over embarrassing diary entries from nearly a decade ago in which he fantasized about becoming a billionaire — even as the then-nonprofit charity got millions in donations from Musk.

“Financially what will take me to $1B?” Brockman wrote in the digital journal in 2017, referring to the idea of converting OpenAI to a for-profit entity.

“We’ve been thinking that maybe we should just flip to a for profit,” Brockman allegedly wrote. “Making the money for us sounds great and all.”

OpenAI President and co-founder Greg Brockman.…