Back then, Mozilla&#x27;s plan was for the CDM to inspect the running Firefox and deny playback if it detects tampering of the relevant browser parts.<p>How the hell that is supposed to work if the CDM is oh-so-sandboxed is left as an exercise for the reader.<p>Did anyone actually check that own builds of vanilla Firefox sources are able to use the Adobe CDM? Wouldn&#x27;t surprise me at all if it only worked with the official Mozilla-signed Windows binaries (yep, at least the Mozilla flavour of the &quot;portable&quot; and &quot;interoperable&quot; EME is provided for Windows and Windows only).