Unknown type 'BeforeUnloadEvent'

`test.js`:
```js
/** @type {BeforeUnloadEvent} */
var a;
```

Compiled with `closure-compiler -O ADVANCED --js test.js --js_output_file test.min.js` version `v20220601`:
```
test.js:1:11: WARNING - [JSC_UNRECOGNIZED_TYPE_ERROR] Bad type annotation. Unknown type BeforeUnloadEvent
1| /** @type {BeforeUnloadEvent} */
^

0 error(s), 1 warning(s)
```

That's strange, since the following executed in the browser:
```js
onbeforeunload = function(e) {
console.log(e);
e.preventDefault();
return "";
};
```
returns `BeforeUnloadEvent` in the console. Why does GCC not support it?