> I have an older mac with older FF. Results: librewolf and waterfox wont run (10.15 min)
That's just because Firefox itself requires at least macOS 10.15. IceCat only works because it's based off of Firefox ESR; once the next ESR comes out IceCat won't work either.
There is a fork of Firefox (which is in fact the web browser I use) that adds back support for older versions of macOS. At the moment, it supports all the way back to OS X 10.8 Mountain Lion. However, this is all it does; it does not contain any additional privacy features above and beyond mainline Firefox. However, I guess it technically isn't a Mozilla product, so you won't need to agree to Mozilla's Terms of Service.
That's just because Firefox itself requires at least macOS 10.15. IceCat only works because it's based off of Firefox ESR; once the next ESR comes out IceCat won't work either.
There is a fork of Firefox (which is in fact the web browser I use) that adds back support for older versions of macOS. At the moment, it supports all the way back to OS X 10.8 Mountain Lion. However, this is all it does; it does not contain any additional privacy features above and beyond mainline Firefox. However, I guess it technically isn't a Mozilla product, so you won't need to agree to Mozilla's Terms of Service.
https://github.com/i3roly/firefox-dynasty/releases