So yes, this is about the anti-circumvention provisions and not related to the takedown procedure that usually comes to mind when the DMCA is mentioned.
Thanks for more info! And excuse my language, but holy fuck Valve is not what it portrays itself to be. Going around and proactively seeking legal approval of third parties, that is NOT what I expected them to do, let alone in a case where an emulator is the core of the issue. They basically preemptively covered their ass just so the 0.1% chance of Nintendo suing them is 0. Nice. Imagine selling a product on Steam and Valve going behind your back and discussing with your competition if it's ok to have your product on Steam (lawyers to lawyers, no courts involved!)... I know it's not the same, but this case doesn't exacly inspire confidence in them being hands off in the future!
So yes, this is about the anti-circumvention provisions and not related to the takedown procedure that usually comes to mind when the DMCA is mentioned.