Matthew Gault writes: “Favicons are one of those things that basically every website uses but no one thinks about. When you’ve got 100 tabs open, the little icon at the start of every browser tab provides a logo for the window you’ve opened. According to a researcher, though, these icons can also be a security vulnerability that could let websites track your movement and bypass VPNs, incognito browsing status, and other traditional methods of cloaking your movement online.”