The only place I am aware of is to look at the source code, in this case it would be the light integration:
# Bitfield of features supported by the light entity
SUPPORT_BRIGHTNESS = 1
SUPPORT_COLOR_TEMP = 2
SUPPORT_EFFECT = 4
SUPPORT_FLASH = 8
SUPPORT_COLOR = 16
SUPPORT_TRANSITION = 32
SUPPORT_WHITE_VALUE = 128
The value is a bitfield, so 19 would be 16 + 2 + 1, which means the light supports transition, color temperature, and brightness (dimming). The meanings of the constants are explained in the developer docs.