| errors | Package errors implements functions to manipulate errors. |
| internal/oserror | Package oserror defines errors values used in the os package. |
| io | Package io provides basic interfaces to I/O primitives. |
| 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. |
| time | Package time provides functionality for measuring and displaying time. |