hello manzeec, the cdm/drm modules in firefox can't be used to spy on you - the technical details about these are explained in https://hacks.mozilla.org/2014/05/reconciling-mozillas-mission-and-w3c-eme/ you can however disable the widevine/primetime decryption modules in the firefox ''menu ≡ > addons > plugins'' panel. since youtube doesn't use them, you'll still be able to watch videos there. (html5 is a basic foundation of the modern web & a totally different matter)