Yog Script (.ys, .yns) analyzed: its lexer, parser and syntax tree, names resolved, the class index model — what the build and the editors read a source with.
namespace System;
/// The base of every attribute: `[Name(…)]` on a declaration is an object
/// of a class inheriting it, read by Reflection at run time and by macros
/// at build time.
public abstract class Attribute {}