diff --git a/docs/api.md b/docs/api.md
index 881d3e5e7c9..91b1bb2d387 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -103,6 +103,9 @@ Currently there are two API groups in use:
    `apiVersion: v1`.
 1. the "extensions" group, which is at REST path `/apis/extensions/$VERSION`, and which uses
   `apiVersion: extensions/$VERSION` (e.g. currently `apiVersion: extensions/v1beta1`).
+  This holds types which will probably move to another API group eventually.
+1. the "componentconfig" and "metrics" API groups.
+
 
 In the future we expect that there will be more API groups, all at REST path `/apis/$API_GROUP` and
 using `apiVersion: $API_GROUP/$VERSION`.  We expect that there will be a way for [third parties to