create-better-t-stack/apps/cli/templates/frontend/svelte/src/app.d.ts

// See https://svelte.dev/docs/kit/types#app.d.ts
// for information about these interfaces
declare global {
	namespace App {
		// interface Error {}
		// interface Locals {}
		// interface PageData {}
		// interface PageState {}
		// interface Platform {}
	}
}

export {};