I think you are not right on this because a file with a Physical_colour part is a file with the colored reference to a normal part.
The Alias is the same part (no color defined) with another number.
So a physical color part can be an alias, but not every alias is a physical color part.
Therefore this is not a duplicate information.
The Alias is the same part (no color defined) with another number.
So a physical color part can be an alias, but not every alias is a physical color part.
Therefore this is not a duplicate information.