I assume at some point Widevine plugin decrypts these files to display the actual video stream in the browser, correct? Why don't they capture already decrypted stream?
DRM is dumb. I used to work on DRM. It was dumb then, it's dumb now.
So while it’s relatively easy to get the raw stream, if you want to re-distribute it, you’ll have to compress it again.
With these leaks, you can get the compressed and decrypted files and re-distribute without any added compression loss.
Maybe I’m wrong, but it’s the only thing that makes sense to me.
Not that I agree with the practice.