| archive/zip | Package zip provides support for reading and writing ZIP archives. |
| encoding/gob | Package gob manages streams of gobs - binary values exchanged between an Encoder (transmitter) and a Decoder (receiver). |
| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| flag | Package flag implements command-line flag parsing. |
| 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/build | Package build gathers information about Go packages. |
| go/importer | Package importer provides access to export data importers. |
| 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). |
| go/types | Package types declares the data types and implements the algorithms for type-checking of Go packages. |
| golang.org/x/tools/go/analysis | Package analysis defines the interface between a modular static analysis and an analysis driver program. |
| golang.org/x/tools/go/analysis/internal/analysisflags | Package analysisflags defines helpers for processing flags (-help, -json, -fix, -diff, etc) common to unitchecker and {single,multi}checker. |
| golang.org/x/tools/internal/analysis/driverutil | Package driverutil defines implementation helper functions for analysis drivers such as unitchecker, {single,multi}checker, and analysistest. |
| golang.org/x/tools/internal/facts | Package facts defines a serializable set of analysis.Fact. |
| io | Package io provides basic interfaces to I/O primitives. |
| log | Package log implements a simple logging package. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| path/filepath | Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths. |
| reflect | Package reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| time | Package time provides functionality for measuring and displaying time. |