While it could be parallel, I found that after subscribing push from https://mozilla-services.github.io/WebPushDataTestPage/ and restarting Firefox 131, sending push does hit PushService and it does send ack, while no service worker gets actually started and no actual notification is sent. 🤔
Bug 1925631 Comment 21 Edit History
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~~While it could be parallel, I found that after subscribing push from https://mozilla-services.github.io/WebPushDataTestPage/ and restarting Firefox 131, sending push does hit PushService and it does send ack, while no service worker gets actually started and no actual notification is sent. 🤔~~ Never mind, that's how the test page SW works, it only postMessages to clients and the clients shows the notification, not from SW.