New iterator composition APIs
ECMA-262 now specifies Iterator.zip and Iterator.zipKeyed, including mode/padding handling and iterator-closing semantics. The new IfAbruptCloseIterators shorthand tightens abrupt-completion cleanup for these helpers.
Atomics grows wait/wake and spin-wait primitives
The spec adds Atomics.pause() as a standardized spin-wait hint, and Atomics.notify to formalize waking agents from wait queues. Together, these updates strengthen the shared-memory concurrency story for engines and authors.
Symbol registry and parsing semantics clarified
[[GlobalSymbolRegistry]] moves onto the Agent Record, making Symbol.for explicitly agent-scoped and better aligned with the execution model. The parsing abstract ops ParseScript and ParseModule were also clarified to accept string/code-point input directly.
Other misc changes
Editorial cleanup continued across subclassing guidance, host-synchronization terminology, and assorted wording/markup fixes throughout the spec.