What does the emperor's "festival" mean in Hanwu the Great?

Equivalent to the current diplomatic card. Holding that thing in your hand means that you are an envoy sent by the emperor, representing your country to negotiate marriage in the other country ~ ~

Not betraying one's country is called "keeping a festival"! !

It means don't give up what you have made of yak tail hair, which means don't turn your back on your country, monarch.