It is a very simple extension and it does not require any permissions. It is an easy and very quick way to scroll to the top of the page. You don't need to be on a specific site. The extension is based on the web browser and it will work on most sites.

When you install it, it will appear as a button in the browser and you will be able to use it by just clicking it. If you want to change the icon, you can do that by right-clicking on it and selecting "Options".