Close Tab Button (Firefox Quantum add-on) is a free add-on for Firefox Quantum, the latest version of Firefox. It adds a "close tab" button to the right side of the tab bar, next to the tab overflow menu. This button allows you to quickly and easily close any open tab. It also adds a "close other tabs" button to quickly close all tabs except the current one. This can be really helpful for quickly cleaning up your browser when you have a lot of tabs open. It also allows you to customize the appearance of the buttons and choose from a range of sizes, colors, and icons.
Discontinued The extension is no longer being developed since 2014 and does not work in Firefox 57. The extension still works in XUL-based Firefox forks such as https://alternativeapp.info/software/waterfox/ and https://alternativeapp.info/ software / palemoon /.