I work for XWiki SAS. Two products we develop have it: - XWiki, a extensible wiki platform, experimentally [1] but soon to be fully supported. - CryptPad [2],

I work for XWiki SAS. Two products we develop have it: - XWiki, a extensible wiki platform, experimentally [1] but soon to be fully supported. - CryptPad [2], an end-to-end encrypted collaborative platform. And actually, CryptPad was accidentally born as a first attempt to have this feature in XWiki. [1] https://extensions.xwiki.org/xwiki/bin/view/Extension/Realtime%20WYSIWYG%20Editor/ https://extensions.xwiki.org/xwiki/bin/view/Extension/Realti... [2] https://cryptpad.org/ https://cryptpad.org/