Do you have a source for that? Everything I've read and can find still shows they haven't signed it.
www.microsoft.com/en-us/corporate-responsibility/topics/open-weight/
Amazon is listed as signatory, I doubt microsoft just decided for them.
alt Hacker News
www.microsoft.com/en-us/corporate-responsibility/topics/open-weight/
Amazon is listed as signatory, I doubt microsoft just decided for them.