Fork Changelog from the standard Svelte REPL:

added mdsvex
added .svx extension for MDSVex files
added ayu-dark css theme
build the workers as es modules (vite default is iife)
tweaked the file extension types
emit 'compiled' event from src/lib/index.svelte with compiled/bundled code for consumption by another component
also emit components from <Repl on:compiled={(e)=> ({compiled, components} = e.detail)} />
added github format markdown (gfm) for .svx and css file for codemirror
set svelte.compile options to {accessors: true} so parent comp can grab schema

@sveltejs/svelte-repl

This is the guts of https://svelte.dev/repl, extracted into its own package so that it can be used elsewhere.