Favicon - MDN Web Docs Glossary: Definitions of Web-related terms 编辑

A favicon (favorite icon) is a tiny icon included along with a website, which is displayed in places like the browser's address bar, page tabs and bookmarks menu. Note, however, that most modern browsers replaced the favicon from the address bar by an image indicating whether or not the website is using HTTPS.

Usually, a favicon is 16 x 16 pixels in size and stored in the GIF, PNG, or ICO file format.

They are used to improve user experience and enforce brand consistency. When a familiar icon is seen in the browser's address bar, for example, it helps users know they are in the right place.