Exactly like YAML does.

With Tanka you would usually use the functions provided by `k.libsonnet` to generate your manifests.

For CRD's, there are no helpers available, so you either just write the plain manifest as a Jsonnet object (JSON syntax), as YAML and `import` it (gives you an object as well) or even better write some helper functions yourself, publish them as a library on GitHub and make future users happy :D

Which extensions are you talking about? Do you mean CRDs? Then it take plain JSON or you can write a function to generate those.

Yes, that is why I am talking about. I guess just providing a new object type for your custom extension should work fine.