If you really want to make a difference, wait until the “non-DRM’d” version comes out, and then use it to access Firefox’s websites. Intentionally change the agent string.
But again, what are you really saying? The DRM really isn’t in there until YOU TELL IT TO COME IN. Mozilla will make this an obvious notification. IF you install it, it’ll go into a very tightly controlled sandbox. Now, it does not.
The only way you will have DRM in your Firefox is if you, and you alone, intentionally download and load DRM into your firefox. Just like it is now.
