Firefox will show me what CSS applies to each entity and what attributes result. I'd like something that gave me the same information textually so I can tweak

Firefox will show me what CSS applies to each entity and what attributes result. I'd like something that gave me the same information textually so I can tweak the CSS, e.g. simplifying specificity without intending to change the end result, and check for changes, e.g. diff(1). Anyone know of such a thing?