Why is Huang Hua written on the post archway of Gaoyou Acropolis?

Used as a courtesy title for past envoys. The inscription "Yellow Flower" on the post archway of Gaoyou Weicheng is a courtesy title for past envoys. Archway and archway are both part of China's architectural culture, which are widely used to show off merit and glory, and are often used in palaces, temples, ancestral halls, offices, gardens, starting points and intersections of main streets. Gaoyou is a county-level city managed by Yangzhou City, Jiangsu Province, located on the north bank of the Yangtze River Economic Belt.