The humble favicon was messily birthed with the pernicious IE5 release. Since that fateful day, browsers have slowly expanded favicon technology to encompass many wildly differing and lightly documented use cases. Here in 2021 favicons are found primarily in browser tabs, home screens, and Google search results, but they continue to pop up in the strangest places.

Recently my team was tasked with building a favicon fetcher. As a warmup, I looked to see how Chrome handles favicon loading. Do you know that the favicon loader in Chrome is many thousands of lines of code? Why is it so complicated?

We realized we knew very little about the favicon ecosystem. Eventually we decided to fetch the Tranco top 100,000 websites and analyze their favicons. We checked each home page for favicons, Apple touch icons, and manifest icons. We also examined fallback locations like /favicon.ico. Here’s a quick table to catch you up: //

The big winner is the mesmerizing favicon from eventhorizontelescope.org, clocking in at a hefty 7MB. When I downloaded this favicon, the density of my machine increased and nearly collapsed into a black hole.