The anonymous donor was Aha! (<a href="http:&#x2F;&#x2F;www.aha.io" rel="nofollow">http:&#x2F;&#x2F;www.aha.io</a>). It wasn&#x27;t as anonymous as we expected because Marijn tweeted it :-), but we are excited by ProseMirror and the opportunity to contribute. WYSIWYG editing is a huge part of what our app does, and so I have always been on the lookout for better ways to build editors. Marijn&#x27;s approach of using a shadow document representation (<a href="http:&#x2F;&#x2F;marijnhaverbeke.nl&#x2F;blog&#x2F;prosemirror.html" rel="nofollow">http:&#x2F;&#x2F;marijnhaverbeke.nl&#x2F;blog&#x2F;prosemirror.html</a>) is the most promising solution I have seen for a while.