Well only just learned that Firefox no longer supports ALSA. Did some delving and Firefox ESR (Extended Service Release) was still supposed to support it but that was a few versions ago! Solution? SlimJet - get it from here:
And I didn't even have to add 'apulse' in front of the command - YouTube worked straight out of the box. My days of Firefox are now permanently GONE! Mozilla Foundation can Firefox Off! I will also be looking at removing Thunderbird too.
I don't think people realise just how much under threat Linux is from within, in particular from Mr Poettering and Red Hat who would love to see /etc be removed from GNU/Linux. The default engine is Bing but you can remove that, including Ecosia that uses the Bing search engine - I have just left DuckDuckGo and slimjet search.
[update: MP4 files won't play in slimjet due to patent issues - solution on this page:
[Update: 02.11.2021 - slimjet are planning to make a version for android and are asking users for suggestions on what should be included. One of the great things that make it so fast is the fact it has an adblocker built in to the browser itself so pages load instantaneously!]