JTL
Yes, it's for NVIDIA graphics cards as AMD ones have this option in their software (think it was Ryzen Master or something along those lines)
But no, it uses the built-in EDID numbers for primaries within the monitor you are using.
From the net:
"Nvidia doesn’t include a similar feature in their graphics drivers, but the Nvidia desktop GPU and driver pipeline does actually include a ‘hidden feature’ that works in a very similar way to clamp the gamut, but without any additional changes to colour channel balance and white point. A tool called ‘novideo_srgb’ can be downloaded here and is discussed in this Reddit thread. Download the latest ‘release.zip’ file and extract the contents to a destination of your choice. Run ‘novideo_srgb.exe’ (Microsoft Defender SmartScreen may flag this as an unrecognised file initially) and click the ‘Clamped’ checkbox. In the vast majority of cases the same EDID data read by the AMD alternative is used and the resulting gamut is extremely similar. The corrections apply universally, including to full screen games and other applications and should apply until you re-open the tool and remove the clamp. The clamp will be temporarily disabled if Windows sends the screen into standby (‘Turn off the display’) after a given amount of time. The clamp will re-apply when your system restarts, but if you don’t wish to do that or stop using that feature in Windows, you’d have to disable then re-enable the clamp after the screen wakes up again.
If you click the ‘Advanced’ tab you can select the colour space you wish to target. The default is ‘sRGB/Rec.709’ but ‘Display P3’ (DCI-P3), ‘Adobe RGB’ and ‘BT.2020’ (Rec. 2020) can also be selected. By default the corrections are based on EDID data as described earlier (‘Use EDID primaries’). The image below shows examples of the Dell Alienware AW3423DW (red triangle) compared to sRGB (green triangle), DCI-P3 (blue triangle) and Adobe RGB (purple triangle) natively and with the corresponding colour space clamps applied. As you can see, the ‘novideo_srgb’ clamps work very effectively to cut down over-extension beyond the selected colour space with only a small amount of additional under-coverage. Naturally, they can’t add in additional coverage beyond what the monitor can display natively.
You can also select ‘Use ICC profile’ and load in an ICC profile (ideally one you created yourself), which is not activated by the tool but is instead simply read to establish the actual measured gamut. This can enhance the accuracy of the gamut corrections, allowing very close sRGB tracking or tracking of your chosen colour space. Native gamma information is also read and you can use the tool to tweak gamma tracking, if you wish. The idea here is to feed better data to the tool from the profile so it can make more accurate corrections. But these corrections assume the monitor is running with its native gamut and gamma handling rather than with the profile actively being used at the same time."
Hope this helps.