Review FF release notes from FF69 to latest (FF75)
Release Notes: https://www.mozilla.org/en-US/firefox/releases/ Developer release notes: https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases
Also, diff prefs.js between latest and esr 68.
Also look at the bugs from 69 to 75 (update target_milestone param for each version)
Mozilla reponed: https://bugzilla.mozilla.org/buglist.cgi?resolution=---&query_format=advanced&product=Core&target_milestone=mozilla69
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