thanks for the answers so far.
I am talking about the color picker 
of this device. You can click on the circle and it reports you values in X and Y - i believe CIE color map.
action_color-x = 338, action_color-y = 163 which represents RED. In HSB code it should be (“0,x,x”).
This thread comes close to it - but it is the other way way: [SOLVED] Convert HSBType to CIE XY needed for Ikea Tradfri control through Deconz REST
also this link : https://github.com/Koenkk/zigbee2mqtt/issues/272 is the other way around.
yes, i am using the new attribute output format