Are these additional 'Camera' profiles (a) Adobe's approximation of second-guessing the manufacturer's intent
Yes. It can't be otherwise, because the whole demosaicing and processing pipeline is different. Even if they could get this (proprietary) information from the manufacturers, it wouldn't produce the same result. So these profiles are strictly for visual appearance.
A raw file doesn't contain anything other than the sensor data - which is a dark, compressed, grayscale image. That's how the sensor records it. The image appears in the processing. That's why different raw processors produce different results from the same file. There is no "original image".
Thanks for the info.
Perhaps I was a bit inarticulate with my choice of words. Whilst the sensor itself only records a greyscale image, my understanding is that the bayer filter determines areas of luminance which are translated into colour information. This information is written into the raw file.
So when I referred to sensor information, what I meant was camera information - which does carry colour description of some kind or another. Surely this is why Canon raw images are considered warm; Fuji; blue etc, independent of the third party image processor being used.
when I referred to sensor information, what I meant was camera information - which does carry colour description of some kind or another.
Yes, and probably in the form of profiles that work with that particular processing engine. The same profile wouldn't work in a different processing engine - any more than Adobe Standard would work inserted into DPP.
Yes, there are metadata tags that record camera settings. These are ignored by ACR - for the same reason: they don't make any sense in the ACR processing engine. The one exception is white balance, but even here, the actual value may be shifted in order to get the same visual appearance. Again the same reason: different processing engine produces different results.
Note that the goal in the "as shot" white balance setting is to produce a comparable visual appearance - even if that means different numbers. So if the engineers at Canon decide they like a warm appearance, and those at Fuji a cool one, that appearance will carry over into ACR.