kubernetes/vendor/sigs.k8s.io/json/internal/golang/encoding/json/tags.go

type tagOptions …

// parseTag splits a struct field's json tag into its name and
// comma-separated options.
func parseTag(tag string) (string, tagOptions) { … }

// Contains reports whether a comma-separated list of options
// contains a particular substr flag. substr must be surrounded by a
// string boundary or commas.
func (o tagOptions) Contains(optionName string) bool { … }