Upgrading or switching the OS is a major undertaking.
I appreciate that Mozilla has fewer resources than Google, but having the latest version of FireFox working only on macOS versions released within the past two years is unnecessarily restrictive in my opinion. I'm an independent software developer far more financially constrained than Mozilla who supports macOS releases going back 10 years. It's just a matter of not using the new API calls shipped with each new OS release and optionally dynamically loading the API calls that are not present on all OS versions.
EDIT: My original post was wrong. Mozilla still supports Mojave. See details above.
Mozilla cuts off support for macOS releases much too early in my opinion. I'm running macOS 10.14 Mojave which was released in 2018 and it only supports FireFox 91. The latest version of FireFox is 96. I can't find a definitive statement what minimum version of macOS is needed by the latest Firefox, but what they list on https://www.mozilla.org/en-US/firefox/96.0/system-requiremen... is incorrect and/or out of date: macOS 10.12.
EDIT: I was wrong. mrpippy pointed out in a reply below that Mojave is still supported by the latest FF release. I was using the FF ESR release which only goes up to FF version 91. Sorry for the noise, and thanks for correcting me.
Years ago I wrote a small toy interpreter based on predereferenced computed gotos with surprisingly good speed. For very small programs without dynamic data allocation churn it could run as fast as 3 times slower than compiled code instead of the expected 10X slower. Good things happen speed-wise when all the byte code and data fits into the L1 cache. Also, branch prediction is near perfect in tight loops.
For whatever reason I can never remember the syntax of <(command) and end up "rediscovering" it every year. It's seldom used but when it's needed it's rather elegant.
Another somewhat related useful bash feature is using this form: