I updated my user-overrides.js for Firefox. Changes include...
* added 'network.trr.mode'
* added 'network.trr.uri'
* added 'network.connectivity-service.*' prefs to testing section
* added 'mathml.disabled'
* added 'browser.download.folderList'
* added 'app.update.silent'
* added 'app.update.service.enabled'
* added 'network.predictor.enabled'
* removed 'network.dnsCacheExpiration'
* removed 'network.dnsCacheExpirationGracePeriod'
* removed 'intl.locale.requested'
* shortened the syntax error check regular expression
There's some cleanup done to the 'ghacks' user.js, so be sure to update it using their updater script followed by running their prefsCleaner script. Do this with Firefox closed. Need help? See Obtaining and maintaining the user preferences files. Leave a comment if that isn't enough.