Elon Musk , the world's wealthiest individual , took the stand for a second day in a landmark trial , accusing fellow OpenAI co-founder Sam Altman of betraying promises to keep the AI company a nonprofit dedicated to humanity's benefit. The trial scrutinizes the 2015 birth of the ChatGPT maker, initially a nonprofit startup primarily funded by Musk, before its transformation into a capitalistic venture now valued at $852 billion. Musk, who invested approximately $38 million in OpenAI from December 2015 through May 2017, testified about the company’s early years. He recounted losing confidence that Mr. Altman would uphold its nonprofit status, stating under questioning from his lawyer Steven Molo that by late 2022 he was concerned Mr.…