Ask HN: Who said that Yan LeCunn signed the FLI open letter?

Hey HN! I'm trying to understand what happened with Yan LeCunn and that FLI open letter. The Guardian today says that the letter "racked up signatures from people who did not actually sign it, including Xi Jinping and Meta’s chief AI scientist Yann LeCun, who clarified on Twitter he did not support it." https://www.theguardian.com/technology/2023/mar/31/ai-research-pause-elon-musk-chatgpt I followed the link to Yan LeCunn's tweet from the Guardian article and in the tweet LeCunn says he did not sign the letter. But who said he signed it? Why does the Guardian say LeCunn's signature was on the letter? I can't find LeCunn's signature on the letter now, but that doesn't say anything on its own. Who said LeCunn's signature was on the letter?