Why is "Bordered Yellow Banner" trending?

Wikipedia Overview

The Bordered Yellow Banner was one of the Eight Banners of Manchu military and society during the Later Jin and Qing dynasty of China. The Bordered Yellow Banner was one of Three Upper Banner armies under the direct command of the emperor himself, and one of the four "left wing" banners. The Plain Yellow Banner and the Bordered Yellow Banner were split from each other in 1615, when the troops of the original four banner armies were divided into eight by adding a bordered variant to each banner's design. The Two Yellow Banners were originally commanded personally by Nurhaci. After Nurhaci's death, his son Hong Taiji became khan, and took control of both Yellow Banners. Later Hong Taiji took the Plain Blue Banner and formed the imperial Upper Three Banners. When Dorgon was regent he switched out the Plain Blue and inserted his Plain White Banner as part of the imperial Upper Three Banners. Later, the Shunzhi Emperor took over the Plain White Banner after the death of his regent, Dorgon, to whom it previously belonged. From that point forward, the emperor directly controlled Three Upper Banners, as opposed to the other Five Lower Banners. Because of the direct control of the Three Upper Banners, there was no appointed banner commanders as opposed to the other five. The emperor's personal guards and guards of Forbidden City and maids were also only selected from the upper three banners.