--- a/Python/errors.c
+++ b/Python/errors.c
@@ -1584,6 +1584,15 @@
 
    An exception must be set when calling this function. */
 
+#ifdef __EMSCRIPTEN__
+/* Optional native embedder notification, before allocation, exception
+ * normalization, audit hooks or sys.unraisablehook. The embedder must not call
+ * Python or retain the exception. Standalone CPython keeps its usual behavior.
+ * This also covers a deleted sys.unraisablehook and hook-argument OOM. */
+extern void web_engine_python_unraisable(const char *exception_type)
+    __attribute__((weak));
+#endif
+
 static void
 format_unraisable_v(const char *format, va_list va, PyObject *obj)
 {
@@ -1598,6 +1607,13 @@
     PyObject *exc_type, *exc_value, *exc_tb;
     _PyErr_Fetch(tstate, &exc_type, &exc_value, &exc_tb);
 
+#ifdef __EMSCRIPTEN__
+    if (web_engine_python_unraisable != NULL) {
+        web_engine_python_unraisable(
+            exc_type != NULL && PyType_Check(exc_type)
+                ? ((PyTypeObject *)exc_type)->tp_name : NULL);
+    }
+#endif
     assert(exc_type != NULL);
 
     if (exc_type == NULL) {