CNet lost their javascript privileges on my machine a long time ago. This extension is a godsend: https://addons.mozilla.org/en-US/firefox/addon/disable-javas...

You might not even need it if you are already using uBlock Origin. It can disable JavaScript both per-site and globally.

Nice. Thanks.

Also for any Firefox Sync users, you can sync about:config preferences:

1. Open about:config

2. Right click > New (Bool)

3. Preference name = services.sync.prefs. + name of setting; true

eg: services.sync.prefs.media.autoplay.allow-muted

Another way is to use a user.js file, place it inside the FF profile folder (~/.mozilla/firefox/random-string.default) contents like this:

    user_pref("browser.download.folderList", 2);
    user_pref("browser.download.useDownloadDir", false);
    user_pref("browser.download.dir", "/tmp");
    // ...

You do have to manually copy it between computers, but putting all the prefs in here is easier IMO than dealing with a large number of services.sync.prefs.xxx in about:config. And you can place the user.js file in Dropbox/etc. and just make a symlink to it on your devices, so changes get synced automatically after the initial setup.

Does that mess with websites using muted video as a gif replacement?

yes