| flag | Package flag implements command-line flag parsing. |
| golang.org/x/tools/blog | Package blog implements a web server for articles written in present format. |
| golang.org/x/tools/godoc/static | Package static exports a map of static file content that supports the godoc user interface. |
| golang.org/x/tools/playground | Package playground registers HTTP handlers at "/compile" and "/share" that proxy requests to the golang.org playground service. |
| log | Package log implements a simple logging package. |
| net/http | Package http provides HTTP client and server implementations. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| time | Package time provides functionality for measuring and displaying time. |