I did as well but I will dig it up the comments that I thought indicated otherwise. I think because the rendering selection at least at one time was always set to relative but even with little Lmcs enabled it I am certain it is now set to perceptual and it is always a pretty good match for the color.org perceptual… relative is much more contrasted and easy to spot with that icc. I looked in the code and its a matrix shaper profile in DT… so maybe it is relative… the code says default intent perceptual but again hard to say maybe that just goes in the setting of the dialog box… In the case of the DT profile relative and perceptual will give the same as there is no LUT so again you may be right the thing is that the output generally is closer to what I get with the the color.org icc perceptual and the relative render is much more saturated and contrasted. There are two other icc from color.org… one is appearance and that one renders relative less saturated and more like what DT produces… It is noted I think if I understand to be more srgb accurate when gamut change is large so maybe this jives with the DT matrix profile… There is a v2 profile 2014rgb.icc which is slightly tweaked to improve on the color casts that could apparently be seen with the original v2 srgb spec… again no idea if that would improve not any rendering over what is produced by DT’s matrix… I guess I will try a set on two or three images and render them all and take a look … I wonder if other that the current one here from @s7habo there are some good test images for gamut… Just thinking about this and how it might interact with the results obtained by tweaking the primaries in sigmoid… that being you end up with a result from your edit but the rendering might impact how faithfully that gets conveyed??
I think I misunderstood this comment
“RGB (web-safe) with relative colorimetric rendering intent is essentially similar to the same profile with the perceptual rendering intent. This is to be expected since the profile doesn’t contain any “intent look-up tables”.”
From this thread
combined with my comparison of the output from DT vs color.org icc profiles it looked more perceptual… but I think you are likely correct…