I sometimes miss push notifications, so I would like to see a history of what and when I have received notifications in the sidebar, like the action bar in Windows.
Push notifications at least those from YouTube in Firefox are a lot less useful. Clicking on the pop up alert does nothing. Clicking on the notification in the action center for a YT live stream does nothing. In Chromium based browser clicking on the popup notification would open up a tab for that YT video.