| 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/build | Package build gathers information about Go packages. |
| go/types | Package types declares the data types and implements the algorithms for type-checking of Go packages. |
| golang.org/x/tools/go/loader | Package loader loads a complete Go program from source code, parsing and type-checking the initial packages plus their transitive closure of dependencies. |
| honnef.co/go/tools/gcsizes | |
| honnef.co/go/tools/structlayout | |
| honnef.co/go/tools/version | |
| log | Package log implements a simple logging package. |
| os | Package os provides a platform-independent interface to operating system functionality. |