Edit: It's said to be a downloadable extra at user option.

The Moz page description of the sandbox says the CDM won't have any system access, so it could not distinguish whether PMP is there or not, except maybe by flags in the input from the browser. So either the Mozilla sandbox-CDM can't work as described or PMP won't be required.

Someone correct me if I've missed something there.

So were about to see Iceweasel fork a bit more from base firefox and add a button to render the "encrypted" content to file?

10/10 media industry, you guys are just the absolute best about sticking your fingers in your ears and singing lalala while substituting reality with your own where electrical charge isn't replicable.