What are tags in Go structs for and how to use them?

Hello everyone! I recently started learning Go, and I'm interested in this question: what are tags in structs for? I see something like this in library code:\n\n```go\ntype User struct {\n ID int `json:"id"`\n Name string `json:"name"`\n Email string `json:"email"`\n}\n```\n\nOr:\n\n```go\ntype Config struct {\n Port int `yaml:"port"`\n Host string `yaml:"host"`\n}\n```\n\nI understand that this is somehow related to JSON and YAML, but I don't fully understand the mechanism. How does Go process these tags? Can I create my own custom tags? And most importantly — why are they needed at all, if I could just use the struct field names?\n\nFor example, why not just use `json:"ID"` instead of `json:"id"`? Or what if I want a field to have a different name in code and during serializ