Works as of Pale Moon 28.0.1. The options menu isn't visible from about:addons - you need to click the icon in the toolbar to access it, but after that you can just hide the icon. Good replacement for Procon Latte which no longer seems to work. Includes ability to add your own words.
EDIT: after trying it out on my home PC, I've noticed it makes the browser run terribly slow, so unfortunately I'm going to have to ditch this one for now.
I would give this more stars if I could compose text in Yahoo mail and Facebook text areas. But the extension scrambles the text and randomly re-positions my cursor. Hopefully a fix is coming soon for that...because this is the only filter script I've found that will work on Facebook pages. I'd love to be able to type my posts in the input area rather than on Notepad and then have to copy/paste. Not wonderful. I tried adding filters but most have done something wrong. The script would just stop working.
I'll use the script as long as I can stand while waiting for the text area fix, but it is majorly annoying.
This addon is fantastic! It does exactly what it says it does. I used to be really nervous about browsing some of my favorite websites just because curse words make me anxious, but now I can participate in fun activities without any fear. I use the "custom" filter option, so cuss words now show up as "~*I like ponies*~" for me. I actually look forward to finding profanity now just because it's so amusing to read with the custom filter in place. :)
My only critique (besides the text field glitch that has already been mentioned) is that it doesn't detect cuss words when they're used in various tenses. For example, it detects "f***", but it doesn't detect "f***ing" or "f***er". You can add those additional tenses as "stop words", but it can be a little uncomfortable for people who don't like cussing in general to have to type the words themselves. But other than for that, this addon is a godsend! Thank you so much for making it available! :)