An exported field is a Go structure field whose visibility lets external mechanisms access its value. JSON decoding requires exported fields so the decoder can write into them; templates can read them with {{ .Field }}. section 3.1.3 section 11.6
Bookworm data structures
Bookworm, Books, Author, and Title are exported fields because their names begin with uppercase letters. JSON tags connect these fields to names such as name, books, author, and title, allowing encoding/json to populate the structures. section 3.1.3
