Earlier quoted context omitted.
I'm wondering whether any legal team or similar have donated some time to figure out whether this is actually fair use or to set a precedent, because looking from the outside in, it clearly looks like an implementation meant to circumvent some form of intentionally-obfuscated protected handshake or access control. From a strictly code based POV, it is intended to download protected objects with tests to ensure that p…
That code is protection for YT TOS, not copyright law. If YT want's to use dcma in this way it should claim copyright of all posted material and see how that works out for them. Even if it the video's were copyrighted, it could be still be downloaded for fair use purpose rather than infringement. RIAA is using takedown's to protect google ad money, which is not the intended purpose of that legal action.
Youtube stores cache files to a user's computer, obfuscated so they can't be easily copied or accessed, most likely as part of the terms of their license. That is legally sufficient to constitute a copyright protection scheme.