| errors | Package errors implements functions to manipulate errors. |
| io | Package io provides basic interfaces to I/O primitives. |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| syscall/js | Package js gives access to the WebAssembly host environment when using the js/wasm architecture. |
| unsafe | Package unsafe contains operations that step around the type safety of Go programs. |