| bytes | Package bytes implements functions for the manipulation of byte slices. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| golang.org/x/tools/internal/diff/lcs | package lcs contains code to find longest-common-subsequences (and diffs) |
| log | Package log implements a simple logging package. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| unicode/utf8 | Package utf8 implements functions and constants to support text encoded in UTF-8. |