Font Finder (revived) от Andy Portmen, Eric Caron

"Font Finder (revived)" is WebExtension implementation of the XUL "FontFinder". This extension is created for designers, developers and typographers. It allows a user to analyze the font information of any element on a page, copy any piece(s) of that information to the clipboard.

Preview:
https://www.youtube.com/watch?v=CGI3Atdzt64

"Font Finder" has 3 key pieces of functionality:
1. Any font on a page can be completely analyzed
2. Any piece of an element's information can be copied to the clipboard
3. Any active element can have any piece of the font's options (such as color, size or family) adjusted inline

Any of these options can be quickly accessed through highlight & right-click, or right-click on page and inspect element item.

Information Captured:
1. Font color (rgb and hex)
2. Background color (rgb and hex)
3. Font family (including actual font being rendered!)
4. Font size
5. Line-height, vertical-align, letter and word spacing
6. Font weight, style, variant
7. Text transform, decoration, align and indent
8. Element's type, class and ID

For FAQs and bug reports please visit:
https://webextension.org/listing/font-finder.html

Localization:
https://www.transifex.com/portmen/font-finder/dashboard/