Package builtins holds code generated from the builtin plugins.

Package error has contextual error types.

Package loader has a data loading interface and various implementations.

Package localizer contains utilities for the command kustomize localize, which is documented under proposals/localize-command or at https://github.com/kubernetes-sigs/kustomize/blob/master/proposals/22-04-localize-command.md.

Read docs/plugins.md first for an overview of kustomize plugins.