There was the TodoApp sample with Decompose + MVIKotlin + Reaktive. It was located in the original compose-multiplatform repo, and it was also mentioned in that doc. But eventually they removed all samples with third-party libs from compose-multiplatform, and a member of the community copied the code to https://github.com/IlyaGulya/TodoAppDecomposeMviKotlin. And the link to the sample in the doc was updated. But seems now it's completely removed.
Oh, you are talking about Confetti specifically. Yeah, we could make a PR I guess.