kubernetes/staging/src/k8s.io/client-go/tools/clientcmd/merge.go

// recursively merges src into dst:
// - non-pointer struct fields with any exported fields are recursively merged
// - non-pointer struct fields with only unexported fields prefer src if the field is non-zero
// - maps are shallow merged with src keys taking priority over dst
// - non-zero src fields encountered during recursion that are not maps or structs overwrite and recursion stops
func merge[T any](dst, src *T) error { … }

func mergeValues(fieldNames []string, dst, src reflect.Value) error { … }

// hasExportedField returns true if the given type has any exported fields,
// or if it has any anonymous/embedded struct fields with exported fields
func hasExportedField(dstType reflect.Type) bool { … }