SvelteKit 3 Reaches Release Candidate, Moves Config to Vite and Retires $lib Alias

The Svelte team has moved SvelteKit 3 into the release candidate phase. Configuration moves from svelte.config.js to vite.config.ts, the $lib alias is replaced by #lib via Node's native subpath imports, and file extensions are now required. The framework requires Svelte 5 and Vite 8 with the Rolldown bundler.

• Config moves from svelte.config.js to vite.config.ts for synchronous reads
• $lib alias replaced by #lib, file extensions now required
• SvelteKit 3 requires Svelte 5 and Vite 8 with Rolldown bundler
• Remote functions remain behind an experimental flag