There's also a firefox-bin. Anyone know what the difference between firefox and firefox-bin is nowadays?

I believe that in the far past firefox-bin was the firefox binary, and firefox was a shell script that would do things like notice you already have a firefox-bin instance open and signal it to open a new window rather than launching a new firefox-bin instance.

But nowadays, firefox and firefox-bin seem almost the same. On the current release version on Mac, for example, both are binaries, with firefox-bin 40320 bytes and firefox just 16 bytes bigger.

Info.plist in /Applications/Firefox.app/Contents gives firefox is the executable to run. I'm not sure what role firefox-bin has now, if any.

Grabbing the source and building it myself results in firefox and firefox-bin matching.