The Timer by Bozidar Atanasovski

The Timer Add-On is a Firefox browser extension that allows users to set countdown timers with precision. Users can input the desired timer duration in hours, minutes, and seconds through a simple popup interface. The add-on then runs the timer in the background, displaying the remaining seconds as a badge on the add-on icon. When the timer reaches zero, a notification is displayed to alert the user, making it easy to manage tasks and reminders while browsing the web.