It seems like it shows all the fonts found in the CSS. A font like Arial might seem very popular but in reality not show up for most people because it's often the second or third choice.
Love this. Beautiful execution. Would be cool to see how prominently the font is used on each site – viz., what percentage of text on the site uses that font. Also, it would be great to stylize each font name with the font itself. Great work guys.
I'll save you a right-click — they're using Brandon Grotesque.
I love the design of this. What's it built with?
show each font with the font itself could have been nice.