| errors | Package errors implements functions to manipulate errors. |
| html/template | Package template (html/template) implements data-driven templates for generating HTML output safe against code injection. |
| io | Package io provides basic interfaces to I/O primitives. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| text/template | Package template implements data-driven templates for generating textual output. |
| text/template/parse | Package parse builds parse trees for templates as defined by text/template and html/template. |