I made an HTML/DOM viewer you can paste into your console to view or debug any website in 3D. Choose from random/gradient/clear colors or whether layers have sides.

You can save it as a bookmarklet so it's 1 click away. It's just a tiny IIFE JS function.
https://gist.github.com/OrionReed/4c3778ebc2b5026d2354359ca49077ca

3D DOM viewer, copy-paste this into your console to visualise the DOM topographically.

3D DOM viewer, copy-paste this into your console to visualise the DOM topographically. - dom3d.js

Gist
@orion Finally, someone brought back the old firefox 3d debug feature ( https://firefox-source-docs.mozilla.org/devtools-user/3d_view/index.html ).
3D view — Firefox Source Docs documentation

@ilikecats @orion came here to say that! I loved that feature!