How can I obtain the same or similar effect in Firefox as in Chrome devtools's Layers tab?
I'd like to see what layers exist on a page and their dimensions.
It looks like FF had such feature ("3D view") but it was discontinued.
I've found and tried to use http://mozilla.github.io/layerscope/ but it doesn't seem to be what I'm looking for and I'm not sure whether it's working on FF Quantum correctly.
This answer is a part of article from here