You might try using Firefox developer edition - I use it on 8.8 but imagine it should work on 9.x and it shouldn’t affect the system version if you follow the instructions at FF Dev as the user in the thread mentions.
You might try using Firefox developer edition - I use it on 8.8 but imagine it should work on 9.x and it shouldn’t affect the system version if you follow the instructions at FF Dev as the user in the thread mentions.