If a question contains some useful MathJax mark-up that I don't know and want to recycle for use elsewhere, I can "edit" the question, copy the mark-up I want and then cancel my "edit". This isn't an option if I want to see the mark-up used in a comment. Is there a way of seeing the MathJax original source for a commment?
Hover over the mathjaxed-portion in which you are interested, and right click: you can then select "Show math as:" and a menu appears from which you select "Tex commands." A small pop-up window will appear with all the formatting, minus the dollar-signs.
Disclaimer: I'm a windows-user, so I'm hoping this can be modified for mac users!
From the OP: Windows right-click is equivalent to Ctrl+click on a Mac.