Military band performs at Trooping the Colour birthday salute

The video describes a grand spectacle involving over 400 men, focusing on the presentation and trooping of the color by Her Majesty. The color, rich in historical significance, is ceremonially handed to a junior officer, following military customs. The event concludes with a slow march accompanied by music.

What does the color symbolize in relation to the military history of the country?

Describe the music that accompanied the trooping.