[thayne]

And the fact that polkit uses it is why debian and ubuntu use an ancient version of polkit. And fwiw, there is an effort to replace spidermonkey in polkit with something else, like duktape.

Also js78 uses the version of spidermoneky from Firefox 78. The current Firefox ESR is 91 (released in august), but I don't see any js91 package, and https://github.com/mozilla-spidermonkey/spidermonkey-embeddi... still says to use the 78 ESR. Note that ESR78 is end of life and no longer receives security updates.

And from what I understand, there is no attempt at backwards compatibility in the spidermonkey interface, so each upgrade requires a lot of changes to the embedding program.

Yes, it is possible to embed spidermonkey, but there are a lot of challenges.