Sumac

I don't get anything lemony/citrusy from sumac. Not at all. It has got a sour and tart berry flavour. The better the quality, the more berry/fruitiness you will get. Also, premium quality sumac is very dark red and somewhat damp/moist. Cheap quality Sumac will only provide sourness with barely any aroma, is less dark, dry and usually comes with salt added. I have not yet tried it in fried chicken, but I will. Why not.

It would be a perfect napkin item match btw. See below the berries/seeds cut from the KFC napkin and real Sumac berries slightly edited by me.