- fix: cancel deferred event listeners during cleanup ([#18749](https://github.com/sveltejs/svelte/pull/18749))
- perf: speed up parser interactions with Acorn or avoid them where possible ([#18740](https://github.com/sveltejs/svelte/pull/18740))
- fix: prevent effect tree of batches from interfering with each other ([#18508](https://github.com/sveltejs/svelte/pull/18508))
- fix: serialize input default values during server rendering ([#18733](https://github.com/sveltejs/svelte/pull/18733))
- fix: remove `WAS_MARKED` flag in favor of `Set` ([#18127](https://github.com/sveltejs/svelte/pull/18127))
- fix: throw `set_context_after_init` when `setContext` is called after an `await` during SSR ([#18739](https://github.com/sveltejs/svelte/pull/18739))
- perf: avoid regex matching in parser where possible ([#18736](https://github.com/sveltejs/svelte/pull/18736))
- fix: in non-async mode, only push variable to current_sources when active_reaction is updating ([#18550](https://github.com/sveltejs/svelte/pull/18550))
- fix: recognise `aria-braillelabel` and `aria-brailleroledescription` as known ARIA attributes ([#18765](https://github.com/sveltejs/svelte/pull/18765))