Is the power connector labeled "P6" used for a video card?

Hi again!

I want to add a video card to my HP Z230 i7 4790 (tower).

I know it has a 400 watt supply so any of the cards I am thinking about will work (example 1050 Ti is about 75 watts).

I see some of the cards have a 6 pin connector for extra power (some have a 6 and an 8 ... I know these draw too much power for my unit).

I see a connector in my computer that is not used.  It has 6 pins and it is labeled "P6".

Is this connector for a PCI-E video card or for some other use?

Thanks .... Mike