In the recent days, after the release of Android Jelly Bean 4.3, I've heard about a new feature: something like a notification history, which would be a screen showing not only the current notifications but also past ones. Is it true or is it just a rumor? If this actually exists, how can I get to such screen?
This is not a rumor: the notification history is a true feature from Android 4.3, although they don't make any mention of it in their What's New page.
The following steps will allow you to take advantage from the Notification History in a vanilla Android Jelly Bean 4.3: