Descriptions of experimental features

[jzelinskie]

I noticed #11355 adds a page with a list of experimental features and their status, but they each lack descriptions of the features themselves. Maybe I've totally overlooked something, but searching the docs didn't yield any content for some of these features.

[jzhou77]

Yes. These features are not ready for production use and subjected to significant changes, such as feature removal or incompatible between versions. So we tend to add documentation after the feature is more mature, which is not ideal.