"Evaluate" option in REPL doesn't work for me

It looks like bundle.run is down, so https://bundle.run/@babel/polyfill@7 fails to load, which breaks the REPL for me 😢

Is there a reason this uses bundle.run specifically, or can it be switched to jsdelivr or Unpkg? Both of them work fine:

We need to use bundle.run when loading individual plugins from npm, but for @babel/polyfill we can use a normal CDN since it's already bundled.