HostBrandColourWrite

One colour to store in the host brand.

namerequired string: The colour's name: letters, digits, underscore and hyphen only, else 422 `regex`. Unique within the list without regard to case; a stored colour of the same name keeps its identity.
redrequired integer: The red channel.
greenrequired integer: The green channel.
bluerequired integer: The blue channel.
alpha number: The opacity from 0 (clear) to 1 (solid), to at most three decimal places. Defaults to 1.

Used by (1)