This addon has been abandoned. DO NOT DOWNLOAD IT OR USE IT IN ANYWAY because it is now DANGEROUS to DOWNLOAD and INSTALL.
This is a warning of what happened to me when I downloaded it.

The Dev, knowing that Firefox has no way to actively monitor the addon(s) which is clearly stated on the d/l page, decided to become nefarious. Once I downloaded the addon, about an hour later the Dev came crashing into my home wearing ONLY a pair of custom made mustard yellow Crocs with high-rise platforms with a scrolling LED sign that said "Xenia, Ohio's Pet kicking Chap of 2004"
She then began running around my kitchen trying to kick my dog who was NAKED!!(The dev, not my dog)
THEN after the marathon dog kicking kerfuffle which I was unable to stop her because she greased her self up with Vaz which made her extremely ungrabbable she then grabbed my cordless landline phone, dialed up some 1-900 Psychic hotline at $9.59 a minute while pouring pure, cane sugar into the gas tank of my pride and joy, my 1987 Escort!

Also, this app no longer works.

Hitting Save in the app settings just makes it reset, It doesn't seem like you can add your own CSV lists/sites to scrape, since saving just clears everything. So I don't even know if the app works because I can't inject any working shift codes to try it.

Wonderful add-on when the game first came out, now I can't seem to get it to navigate through the website properly.

I think this extension is great. However, I play on Stadia, and it doesn't seem to have an option to check or redeem the code on Stadia automatically. Gretchen, if you read this, is there a way for me to add that functionality myself or is that something you would need to do on your end?