diff --git a/core/serialization/blocks.js b/core/serialization/blocks.js
index 6aabb08eebd..673f9c6070e 100644
--- a/core/serialization/blocks.js
+++ b/core/serialization/blocks.js
@@ -60,7 +60,7 @@ exports.ConnectionState = ConnectionState;
  *     enabled: (boolean|undefined),
  *     inline: (boolean|undefined),
  *     data: (string|undefined),
- *     extra-state: (*|undefined),
+ *     extraState: (*|undefined),
  *     icons: (!Object<string, *>|undefined),
  *     fields: (!Object<string, *>|undefined),
  *     inputs: (!Object<string, !ConnectionState>|undefined),
diff --git a/core/utils/toolbox.js b/core/utils/toolbox.js
index 0324c0b2934..947aebe092f 100644
--- a/core/utils/toolbox.js
+++ b/core/utils/toolbox.js
@@ -40,7 +40,7 @@ const {ToolboxSeparator} = goog.requireType('Blockly.ToolboxSeparator');
  *            collapsed: (boolean|undefined),
  *            inline: (boolean|undefined),
  *            data: (string|undefined),
- *            extra-state: (*|undefined),
+ *            extraState: (*|undefined),
  *            icons: (!Object<string, *>|undefined),
  *            fields: (!Object<string, *>|undefined),
  *            inputs: (!Object<string, !ConnectionState>|undefined),