This extension is a utility that displays the number of days since a given date. It allows you to change the date by right-clicking the icon and selecting "Options".

When the button is clicked, a small window will appear with a text box and a drop-down list. The first time you run the app, it will ask you to enter a date. 

The app is useful for keeping track of the number of days between two dates. It is a tool that is easy to use and is very reliable. It displays the number of days in the toolbar and allows you to add or remove the date. It is a free app that does not require any payment to use.