Xcode 12.0.1 has a Persistent Token Extension template. Note that extensions are limited in size. The exact size varies but is 5-6Mb Be careful about the frameworks and libraries in your extension. If your extension is too big, an error will be logged.

There is enough logging in iOS to show when your extension loads and unloads. Your extension can't be too large or it will not load - and that is logged too.