diff --git a/packages/ohm-js/extras/index.d.ts b/packages/ohm-js/extras/index.d.ts
index bc03ee4e..506721be 100644
--- a/packages/ohm-js/extras/index.d.ts
+++ b/packages/ohm-js/extras/index.d.ts
@@ -1,4 +1,4 @@
-import {BaseActionDict, Grammar, MatchResult, Node, Semantics} from 'ohm-js';
+import {MatchResult, Grammar, Semantics} from 'ohm-js';
 
 interface LineAndColumnInfo {
   offset: number;
@@ -44,17 +44,3 @@ interface Example {
  * `//- "shouldn't match"`. The examples text is a JSON string.
  */
 export function extractExamples(grammarsDef: string): [Example];
-
-export type StoredAttributeSetter<T> = (node: Node, val: T) => T;
-
-/**
- * Add a stored attribute named `attrName` to `semantics`. A stored attribute
- * is similar to a normal attribute, but instead of being lazily computed, the
- * value for each node is initialized by an initialization operation.
- */
-export function addStoredAttribute<T>(
-  semantics: Semantics,
-  attrName: string,
-  initSignature: string,
-  actionProducer: (setter: StoredAttributeSetter<T>) => BaseActionDict<void>
-): Semantics;
diff --git a/packages/ohm-js/extras/index.mjs b/packages/ohm-js/extras/index.mjs
index 44a8b2f1..4e0b03d7 100644
--- a/packages/ohm-js/extras/index.mjs
+++ b/packages/ohm-js/extras/index.mjs
@@ -2,4 +2,3 @@ export {getLineAndColumnMessage, getLineAndColumn} from '../src/util.js';
 export {VisitorFamily} from './VisitorFamily.js';
 export {semanticsForToAST, toAST} from './semantics-toAST.js';
 export {extractExamples} from './extractExamples.js';
-export {addStoredAttribute} from './storedAttributes.js';