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.Collections.Generic;
/// What can be gone through, an item at a time (`foreach`, LINQ).
[Intrinsic]
public interface IEnumerable<out T> {
readonly IEnumerator<T> GetEnumerator();
}