Don't hide anything. What does the expression pack mean in detail?

This sentence means an online buzzword, which is used to encourage people to share what they have, especially what is regarded as unique or interesting.

"Don't hide anything" is an online buzzword to encourage people to share what they have, especially what is considered unique or interesting. In the context of Yan characters, this sentence is often used to encourage people to share all kinds of interesting things collected by Yan characters. Emoji package is a special image or animation, which is often used as a way to express emotions or opinions in electronic communication (chat applications).