ADF Faces: what is this _afrLoop parameter in ADF aplications URLs

When you access your ADF Faces application and navigate through the different pages, parameters like "_afrLoop" are added dynamically to the URL.

Because I had some problems to find informations regarding _afrLoop parameter, when I found finally needed informations, I decided to share them:)

As Oracle says parameter called New Window Detection Token: "is an unique identifier that is used by ADF Faces java script to determine if the current browser window is new or an existing window it's managing."

In addition, I found the info, that in ADF Faces 12c this "feature" is disabled.

But let's start from the beginning. I started looking for informations about _afrLoop cause of strange problem in my Webcenter Portal Application. Well, after the one of deployments I couldn't log in because of continuous reloads of the login page within the Internet Browser. While reloading, the value of the URL parameter _afrLoop was each time increased.
As it turned out I sought for the cause of the problem in wrong place. The problem was caused in the error in one of shared libraries.