| bytes | Package bytes implements functions for the manipulation of byte slices. |
| 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. |
| io/fs | Package fs defines basic interfaces to a file system. |
| 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. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| testing | Package testing provides support for automated testing of Go packages. |
| testing/fstest | Package fstest implements support for testing implementations and users of file systems. |
| text/template | Package template implements data-driven templates for generating textual output. |
| time | Package time provides functionality for measuring and displaying time. |