Solidity Libraries Can Now Have State Variables

Solidity libraries can now have/create/use/modify state variables using Diamond Storage.

See this article about it: https://dev.to/mudgen/solidity-libraries-can-t-have-state-variables-oh-yes-they-can-3ke9

Brilliant!
This is so useful, I think it needs its own Informational EIP.
I have raised a topic about that.