Yep, that's something Firefox manages the right way I think (in about:config). Each setting can be in different state: - default value - explicitly set to so

Yep, that's something Firefox manages the right way I think (in about:config). Each setting can be in different state: - default value - explicitly set to something As such, parameters set to the default can (and should) be changed in further upgrades, explicitly changed values should be kept, unless they don't make sense anymore.