diff --git a/packages/react-dom/src/client/ReactInputSelection.js b/packages/react-dom/src/client/ReactInputSelection.js
index 6ee2351b46ff..d4b47b992ce8 100644
--- a/packages/react-dom/src/client/ReactInputSelection.js
+++ b/packages/react-dom/src/client/ReactInputSelection.js
@@ -22,6 +22,11 @@ function isInDocument(node) {
  * Input selection module for React.
  */
 
+/**
+ * @hasSelectionCapabilities: we get the element types that support selection
+ * from https://html.spec.whatwg.org/#do-not-apply, looking at `selectionStart`
+ * and `selectionEnd` rows.
+ */
 export function hasSelectionCapabilities(elem) {
   const nodeName = elem && elem.nodeName && elem.nodeName.toLowerCase();
   return (