[theamk]

It is a commercial hardware, and author wants to get some money back from it. Nothing wrong or shameful about this, as long as this is clearly stated from day 1 (and it is).

At least they provide full schematics here, which is better than many other products do.

[snvzz]

Sure. Issue is particularly with the name, "PD-64", which suggests Public Domain (it's far from!). It may well be unintended.

C64 PSUs are C64 killers, which is why I feel strongly there should be as little as possible in terms of barriers to getting a replacement.

Yes, it is far better than the alternative (no schematics), as at least we can learn how it works without reverse-engineering, as well as build our own legally (just not sell).

[theamk]

The title actually mentions "USB PD" - that's USB Power Delivery, the electrical magic which can increase voltage over USB lines to 12V, and increase power correspondingly.

Without USB-PD (or similar technologies), the max power over USB is limited to 10W (- wire loss), so it would not be enough to power C64 reliably. So it was included in the name.

So I am pretty sure that "PD" in the title has nothing to do with public domain.

[snvzz]

Yes, it is unfortunate.