| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| go/ast | Package ast declares the types used to represent syntax trees for Go packages. |
| go/parser | Package parser implements a parser for Go source files. |
| go/token | Package token defines constants representing the lexical tokens of the Go programming language and basic operations on tokens (printing, predicates). |
| google.golang.org/protobuf/compiler/protogen | Package protogen provides support for writing protoc plugins. |
| google.golang.org/protobuf/internal/encoding/messageset | Package messageset encodes and decodes the obsolete MessageSet wire format. |
| google.golang.org/protobuf/internal/encoding/tag | Package tag marshals and unmarshals the legacy struct tags as generated by historical versions of protoc-gen-go. |
| google.golang.org/protobuf/internal/encoding/wire | |
| google.golang.org/protobuf/internal/fieldnum | |
| google.golang.org/protobuf/internal/genname | |
| google.golang.org/protobuf/proto | Package proto provides functions operating on protocol buffer messages. |
| google.golang.org/protobuf/reflect/protoreflect | Package protoreflect provides interfaces to dynamically manipulate messages. |
| google.golang.org/protobuf/runtime/protoimpl | Package protoimpl contains the default implementation for messages generated by protoc-gen-go. |
| google.golang.org/protobuf/types/descriptorpb | |
| math | Package math provides basic constants and mathematical functions. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| unicode | Package unicode provides data and functions to test some properties of Unicode code points. |
| unicode/utf8 | Package utf8 implements functions and constants to support text encoded in UTF-8. |