I think this is libreoffice inside a remote-desktop like, html client. Like VNC. I fact the same company eyeOs is offering Microsoft office &quot;on cloud&quot;, something similar as <a href="http:&#x2F;&#x2F;guac-dev.org&#x2F;" rel="nofollow">http:&#x2F;&#x2F;guac-dev.org&#x2F;</a>
My opinion is that this is not html5 editor, It is very high demanding hungry resources consuming and complex architecture. Or I am missing a new release libreoffice HTML5 version?