[anyfoo]

Thanks, that's great context. Do I read it right that the NTSC Apple II generated "artifact colors" (heard that before, but did not know if it applies to the Apple II) through effectively monochrome pixels that just work out to the desired color in NTSC, but since that would not work for PAL (because of the phase flip each line, and because the colors would be different), PAL Apple IIs have some extra circuit to convert artifact color pixels into YPbPr and then modulate that using the TCA650?

[thought_alarm]

Yes, that's right. This page has more info: https://nerdlypleasures.blogspot.com/2021/10/apple-ii-compos...

The PAL color circuit was initially an expansion card for the Apple II+ in 1979. The same circuit was built-in to the later Apple IIe and IIc models.

A novel part of the design is that the TCA650 is actually a PAL decoder chip that is meant to split a composite video signal into YPbPr components. The Apple II drives the TCA650 in reverse to generate the composite signal.