The birds of this project have a coloured flag with a 2 character inscription on one upper leg and a plain coloured ring on the other upper leg.
The color code exists consists of 4 consecutive elements: The color code consists of the descriptions of the flag and the plain ring, both separated by a slash ("/"):
flag (4 elements)
plain ring (1 element)
Example Wf-AA/G. This bird has a white flag with inscription AA on the left upper leg and a solid green ring on the right upper leg.