Optional Readonlyallattach every export (import::from .all, box::use(pkg[...]))
Optional Readonlyexcludeattach all exports except these (import::from .except)
Optional Readonlyincludeattached exports as attachedName to exportName (import::from/box::use selection or aliasing)
Optional Readonlynamespace
Restricts/aliases which exports of a package are attached;
undefinedfields attach every export.