I paid for this sometime ago when it was Chrome only which shows that the author is committed to updating this as it's now on Firefox too. In fact, it's updated so frequently I've created a rule and folder for the emails! A nice problem to have!

It works great and I can definitely recommend it for presenting or sharing sensitive information.

This developer is super responsive and solved all the small issues very quick. I highly recommend this addon as it does exactly what it says. Very useful