api: some fixups post repo merge. (#3103)

Signed-off-by: Harvey Tuch <htuch@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ ca111bc0cfd01c290656d5cfb02b09ba83d417f8

README.md

@@ -1,15 +1,20 @@
 # Data plane API
 
-This repository hosts the configuration and APIs that drive [Envoy](https://www.envoyproxy.io/). The
+This tree hosts the configuration and APIs that drive [Envoy](https://www.envoyproxy.io/). The
 APIs are also in some cases used by other proxy solutions that aim to interoperate with management
 systems and configuration generators that are built against this standard. Thus, we consider these a
 set of *universal data plane* APIs. See [this](https://medium.com/@mattklein123/the-universal-data-plane-api-d15cec7a)
 blog post for more information on the universal data plane concept.
 
-Additionally, all of the documentation for the Envoy project is built directly from this repository.
-This allows us to keep all of our documentation next to the configuration and APIs that derive it.
+# Repository structure
 
-# Further reading
+The API tree can be found at two locations:
+* https://github.com/envoyproxy/envoy/tree/master/api - canonical read/write home for the APIs.
+* https://github.com/envoyproxy/data-plane-api - read-only mirror of
+  https://github.com/envoyproxy/envoy/tree/master/api, providing the ability to consume the data
+  plane APIs without the Envoy implementation.
+
+# Further API reading
 
 * [API overview for developers](API_OVERVIEW.md)
 * [API overview for users](https://www.envoyproxy.io/docs/envoy/latest/configuration/overview/v2_overview#)