Lightroom internals - Print module color management engine input/outputs?

[BCRider]

I understand LR's internal working (ie editing) space is linear gamma Prophoto RGB.   Further, I understand LR assumes any untagged RGB input file is sRGB (and converts accordingly).

Assuming those are correct, I'm wondering:

1) What is the "source space" presented to the print CMM when LR is managing the color space conversion (ie when we supply the ICC printer profile)?  Is it linear gamma Prophoto RGB, normal Prophoto RGB or something else?

2) If LR is set to "Managed by Printer" what is the source color space tag passed to the printer?   Is it the answer to #1 above or something else?

3) What if the source file was an RGB file (either tagged or untagged)...does this change the answer to #1 or #2 above?

Thanks!

[digitaldog]

1. I think I'm correct here but hopefully Eric will chime in if not. Anyway, IF the data is rendered and in a known color space, I think that's sent to the print module. So if you have a TIFF in Adobe RGB (1998), there are no further LR parametric edits applied, I suspect Adobe RGB (1998) not Linear ProPhoto is sent to the print module. IF the data is raw or has LR adjustments, then I'm pretty darn sure Linear ProPhoto is used to process the data. Then that is sent to the print module.
2. I believe that's a function of the print driver or maybe OS, I suspect sRGB. It is probably possible to find out exactly by getting hold of the print data. At least on the Mac, you can turn off the driver, print and examine the PDF spool file OutputIntent profile.

[BCRider]

Thanks a lot Andrew!  I'll go with that understanding unless otherwise corrected!