blinklight oleh Sebastian Noack

Most interactive websites, like mail and chat web apps, change the page title in order to indicate new messages. If that happens in a pinned tab in the background, the tab is highlighted in order to get your attention. With this extension, in addition, an LED will be used, in order to indicate that a pinned tab's title has changed. This is in particular useful, when the browser window is minimized or on another workspace.

In order to pin a tab, right click on the tab and choose "Pin tab".