github.com/wmuizelaar/kpt@v0.0.0-20221018115725-bd564717b2ed/site/book/05-developing-functions/01-functions-specification.md (about)

     1  In order to enable functions to be developed in different toolchains and
     2  languages and be interoperable and backwards compatible, the kpt project created
     3  a standard for the inter-process communication between the orchestrator (i.e.
     4  kpt CLI) and functions. This standard was published as [KRM Functions Specification][spec]
     5  and donated to the CNCF as part of the Kubernetes SIG-CLI.
     6  
     7  Understanding this specification enables you to have a deeper understanding of
     8  how things work under the hood. It also enables to create your own toolchain for
     9  function development if you so desire.
    10  
    11  As an example, you can see the `ResourceList` containing resources in the
    12  `wordpress` package:
    13  
    14  ```shell
    15  $ kpt fn source wordpress | less
    16  ```
    17  
    18  [spec]:
    19    https://github.com/kubernetes-sigs/kustomize/blob/master/cmd/config/docs/api-conventions/functions-spec.md#krm-functions-specification