Most flags use the ISO 2-character country code to access their values. However, some flags don't map to 2-character country codes (Scotland being one example). In this case it uses the sequence black flag, GBSCT (for Great Britain-Scotland, represented using the tag latin small letter codes for the letters) then cancel tag to end the sequence. Changing the middle five to be GBENG gives the English flag and GBWLS gives the Welsh flag.