I mean, I don't want to get into a debate about semantics, but when I open config.json files or kubernetes.yaml files in neovim, i get tab completed fields and values as well as inline errors about unsupported entries. That seems to qualify in my book.
Interesting - but is that because neovim has specifically added support for those formats (i.e. you've got some kind of Kubernetes-specific highlighting, not just generic yaml highlighting code?)
In this case it comes in via the coc plugin, which in turn has a plugin named coc-json, which, among other things, tries to download "well known" json schemas although now that I think about I'm not sure where those live.
