Better Twitch TV for Firefox?

If you get BTTV for Firefox on NightDev or I have to be afraid of malicious software. I thought BTTV would have to be found at about: addons but is not it?

Chrome is out of the question for me.

I mean this website: https://nightdev.com/betterttv/#

Nightdev are the developers of the addon. Of course you get the addon from there.

That's exactly what I did not know, thank you.