In case you want to change the release channel in Firefox on MacOS you have to edit the file:
On MacOS you will find this file in the following location:
Simply open it in your favorite text editor and change the “release” option to what you want. You can also navigate there via Finder. Simply go to Applications and right click on Firefox. Choose “show package contents” and you are good to go.
Possible options are:
At some point it was possible to change the update channel in the front-end in about:config. This doesn’t work anymore! You have to edit the channel-prefs.js file.
After a browser restart your update channel will be changed.
If you don’t know what you are doing you should keep it at the default (release). ESR is kind of an long term support version aimed at companies that don’t want to update that often and make maintenance for the IT department easier.