Web Push Notification is supported on Desktop Chrome and FireFox browsers, and Android devices using Chrome or FireFox. iOS phones and Tablets do not provide support yet. Apple have their own proprietary push system. On Dekstop, you may need to leave your browser open to received notifications. Sadly neither Desktop or Android devices provide a way to view a history of push messages.
You are already subscribed.
You requested a "Test Notification". It should arrive on your device within 5 minutes.