Unfortunately David, ALL versions of Firefox ESR starting with version 115 broke with TidBITS Talk for me as my iMac is maxed out at MacOS 10.13.6. Firefox-Dynasty 143 is the only browser that will work here under MacOS 10.13.6. I’m hoping to get an iMac that will allow 10.15.6 to run on it because Firefox ESR 140 will run on that MacOS and still let me come here. I’ll check out Momiji though.
This is useful information but can I suggest the OP/Adam changes the title to something like
Running Firefox browser on older macOS and iOS systems
There is also a related discussion:
On a slightly more on topic question…what is the version number of Mail under Tahoe? (I’m running Sequoia)
Version 16.0 (3864.600.51.1.1)
from Tahoe 26.5
Curious, I have Version 16.0 (3826.700.81.1.8) with Sequoia 15.7.7…