That PDF is about undocumented Z80 features discovered over the years. That video is not about "The Z80's protected mode discovered after 40 years…" That video

That PDF is about undocumented Z80 features discovered over the years. That video is not about "The Z80's protected mode discovered after 40 years…" That video instead should have been titled "My janky hack to isolate Z80 IO space" hence its click-bait title. If it had been titled appropriately I would not have wasted time seeking about looking for the recent discovery. Since there have been pretty astounding discoveries over the years I was pretty upset by the video hoping for a new one. I hope he doesn't pull a stunt like this again.