A great add-on and a safe add-on such as demonstration on website virustotal.com, a website that uses a lot of engines against virus and others computer infections...

A Tip: How download without install this add-on on firefox?

That's simple -> click on Button with a right mouse button -> [+ Add to Firefox] <- and click in option [Save Link as...] and download it -> [Download File] to save it.

Scan info: https://www.virustotal.com/#/url/5fe00aebefa4ce27352b1b98d69c1b31413d92a5e97d9856b8212654a551b3c7/detection