| This feature provides the conceptual ability to create and host a surface that |
| is configured externally, an "external surface". Some off device source will |
| build and assemble content into opaque data from the client's perspective. When |
| this data is handed to xfeature, native views will be provided back, allowing a |
| highly performant and interactive page or part of a page that is also completely |
| data driven. |
| |
| Note that this location defines mostly just the interfaces for this feature. The |
| bulk of the actual implementation is provided by downstream. This means that |
| changes to these interfaces will likely cause downstream build failures. Please |
| do not TBR changes through without engaging OWNERS. |
