The arguments the type's *alias* was written with, by id (§4.9). On the declaration form of a generic alias these are its own parameters - `type Mapper = (t: T) => T` leaves the function type itself parameterless, so this is the only place `T` appears.

`extends` bases of an interface or class instance type, by id.

`T extends U ? X : Y` (§4.11), where the type is one.

A type parameter's `extends` bound, by id (§4.9). Only type parameters carry one.

A type parameter's default type argument, by id (§4.9).

Index signatures (§4.10). Kept apart from `Members` because they are not properties: they have no name, and a type may carry one with no members at all.

The constituents of an intersection, in the checker's order. Separate from `UnionMembers` because the two mean opposite things and the passes that read one must never see the other.

The group the type's own symbol is declared in (O7). Meaningful for object types; primitives and unions stay `Unclassified`, which dispositions as the entry group.

Name of the type's own symbol where it has one - what a `reference` emission templates with, and what a widening finding names.

A tuple's per-element flags, in element order, copied off its *target* - the wire carries them there, not on the reference. The target itself is deliberately left out of the table: deriving it drags all of `Array.prototype` in again for every distinct tuple shape, and nothing but these flags is wanted from it.

Type arguments of a generic reference, resolved for *every* group - an external `Array` carries entry-package types that must still be reached (O7 note).