In modern C#, everything's an interface.

Zig is actually sort of similar. I guess I owe it to C# for teaching me the magic.

Sorry, I mean:

IZig is IActually ISort of ISimilar. (IContinued...)

That is probably the last thing that survived the OOP era... (Yes yes, today it is still OOP) But new developpers don't know about all the different patterns anymore (factory, decorator, prototype, singleton...) We are going back to functional programming and using OOP here and there.