One quick solution would be to just select everything (CTRL A), well at least text, and then copying (CTRL C) to the clipboard.
One can then PASTE (CTRL V) the text in some text editor and get rid of anything else one didn't wanted.

And I still think, (CTRL I) should be zoom-IN and (CTRL O) should be zoom out. With mobile devices zoom has come an important and OFTEN used feature, so it deserves to have mappings in CTRL (A-Z) area of the physical keyboard map, as clipboard select/copy/paste already does.

CTRL I as "Info" is seldom used by most of the users even in desktop Firefox, so "info" wouldn't "deserve" a shortcut in that limited CTRL (A-Z) area IMHO.