So in other words, he was told if he didn't resign he'd be fired. Let's not play games, he wasn't going to survive that episode.
> The Mozilla Board that appointed him knew about his donation
I seriously doubt that, unless checking a person's political donations is a standard course of action Mozilla takes -- which would open a major can of worms (you didn't promote me because I donated to Trump). The whole episode reeked of someone digging around and raising a stink shortly after he made a highly visible move -- otherwise, why did no one in the "community" take issue with his donation in the several years prior?