This is probably chrome desktop notifications. The box to enable them on a website looks quite a lot like one of those "do you want cookies?" Boxes, so it's eas

This is probably chrome desktop notifications. The box to enable them on a website looks quite a lot like one of those "do you want cookies?" Boxes, so it's easy to click without thinking about it. They are (to me) one of the most user-hostile features chrome has added, because it's non-obvious what they are, and how to disable them. You can configure them somewhere in settings (I am on my phone right now).