Why does Facebook notification appear in Chrome? (Even when I'm not online)?

Question

Facebook

FaceBook has recently started showing a notification in Chrome as if an extension was installed or a Facebook tab was opened. There are no extensions and no tabs either.
Why do these notifications appear?
SCREEN of notifications take.ms/i0Lzo

Answer 1

This is called web push. We do this in our system.
More details https://pushall.ru/blog/whatispushnotifications
For example, even this request from Toster I received a push.
Through the IT questionnaire channel, there was an article about him on Habré. https://habrahabr.ru/post/274361/
And yes. web pushes work without installing anything. It's just that the browser is requesting notifications, and if you allow it, then the GCM service will launch a service worker to display the push on the screen when a push arrives. Everything is simple.
The screen that I threw is a push that came through the add-on (this is me so that there is no confusion)