This is a neat idea for a research project. The big map is fun, but the research had some tidbits in it worth looking at.
The average favicon network request takes 130ms, at least from our speedy cloud instance.
Fast, but not that fast, particularly for a file that nearly every website in the world has. All the more reason to get it right and ensure only one is downloaded (ideally SVG).
I would have guessed most favicons are ICO, but no:
The vast majority of the favicons offered up by websites are PNG. 71.6% of
<link rel=”icon”>images are PNG.
/favicon.icofiles are secretly PNGs
One of the reasons that file extensions, to browsers, are rather meaningless. It’s all about that content-type.
Also, they question the accuracy of the method, but the dominant color in the analysis so far is purple. I hope it ends up true as it kinda makes sense. Unless you’re offering different favicons for dark mode, using white or black seems too dangerous these days.