Remind Task - Never Forget Any Task or Todo од Abhishek Sharma

Multitasking is a myth. This extension thus helps you set remainders for later while allowing your mind to be free now and work on current task. After installing, click on icon in browser extension toolbar, then set / view remainders, then at set time you see a new tab opening in browser with that task written in it. Remainders will persist even after system shutdown and restart, then you see remainder next time you open firefox.
Notification remainders is currently not made, as firefox as experimental support for notifications.