Can be tested locally using this snippet (which I think I took from a test...):
```js
let addonId = "test";
let policy = new WebExtensionPolicy({
name: "Scapegoat",
id: addonId,
mozExtensionHostname: Services.uuid.generateUUID().number.slice(1, -1),
baseURL: "file:///",
allowedOrigins: new MatchPatternSet([]),
localizeCallback() {},
});
policy.active = true;
ProcessHangMonitor.showNotification(window, { addonId, scriptBrowser: { browsingContext: { watchedByDevTools: false }} });
```
Depends on D194315
Differential Revision: https://phabricator.services.mozilla.com/D194316
35ecc0e4a7