diff --git a/doc/api/_toc.md b/doc/api/_toc.md
index 69f89af5abb..29b264e77b3 100644
--- a/doc/api/_toc.md
+++ b/doc/api/_toc.md
@@ -1,5 +1,8 @@
 @// NB(chrisdickinson): if you move this file, be sure to update
 @// tools/doc/html.js to point at the new location.
+
+<!--introduced_in=v0.10.0-->
+
 * [About these Docs](documentation.html)
 * [Usage & Example](synopsis.html)