Natasha Sarkar

@KnVerey This is ready for review!

/cc @koba1t @annasong20

/hold So that this isn't merged until release

> Thank you, Natasha! I have a follow up question. When you say "at least two releases", are those minor version releases of kustomize or major version releases? Any two...

> A couple copy-paste things to clean up. Should we mention kustomize edit fix for any of these? Done! And added a warning that the automatic vars->replacement conversion may fail.

/unhold

Taking a look at the [nephio demo controller](https://github.com/nephio-project/nephio-controller-poc) and comparing it to the DownstreamPackage discussed in my above [doc](https://github.com/GoogleContainerTools/kpt/issues/3488#issuecomment-1249583173), I think there are a number of similarities and perhaps functionality...

> I wonder if PackageVariant is a better name than DownstreamPackage. 👍 I like this. I can change the name in a subsequent PR.

@johnbelamaric The basic implementation is done, so wdyt about closing this issue? I think other enhancements are captured by https://github.com/GoogleContainerTools/kpt/pull/3827, and we can discuss release of these controllers separately

Has the `+` sign ever worked in a previous version of kustomize? If not, then I don't think we want to add support for it now. Kustomize cannot, for license-related...