Docsy doesn't break keyboard scrolling in Qutebrowser. Tract does not work for me at all. Also, while I'm sure it's configurable, the neon pink is burning my eyes in a dark room and constrasts terribly with bright white.
For a documentation thing like this, I’d generally recommend avoiding a separate scrolling pane for the primary content, but rather arranging so that it can use the document’s scrolling element. This gets the scrollbar in the place people generally expect it in web things, and makes it work regardless of whether the JS loads.