| cmd/go/internal/base | Package base defines shared basic pieces of the go command, in particular logging and the Command structure. |
| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| golang.org/x/mod/modfile | Package modfile implements a parser and formatter for go.mod files. |
| golang.org/x/mod/module | Package module defines the module.Version type along with support code. |
| golang.org/x/mod/semver | Package semver implements comparison of semantic version strings. |
| internal/lazyregexp | Package lazyregexp is a thin wrapper over regexp, allowing the use of global regexp variables without forcing them to be compiled at init. |
| net/url | Package url parses URLs and implements query escaping. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| path | Package path implements utility routines for manipulating slash-separated paths. |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| 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. |