What happens in the background when you open a file from LR to PS (edit in)?
Does LR export a .tiff (or .psd) to PS, or does LR send the file together with xmp-data to ACR behind the scene and ACR opens a rendered file in PS?
I have a vague memory of older LR and PS versions opening files from LR to PS as tiff (or psd).
Nowadays a file opened from LR to PS show up as .CR2, .NEF, .DNG etc, which of course is not a raw file, but a rendered pixel file.
But what happens behind the scene?