There's no need for it. The image isn't even done particularly well. It's too specific to a browser scenario with some information not properly reflected/explained in the legend.
I have no reason to try make my own or look for an alternative. If someone is particularly interested they can look online for more or less broad explanations as they see fit.
Sessions are technically implemented in a non-singleton approach, and the issue that provoked this comment has since been fixed (context data <-> license mismatch).
rlaphoenix