Under the hood
The UI message batching function was rebuilt to accept swappable run, schedule, and warn functions
What
The internal function that batches and dispatches queued ui.message chains was rewritten so its run, schedule, and warn behaviors can be swapped out, instead of being fixed. By default it still uses the same real implementations as before (a function called yft for running, a setTimeout-based scheduler for scheduling, and the standard warning logger).
Why
This is an internal refactor that makes the message-batching logic easier to test or override, without changing its default behavior for everyday use.