How to only include (or !exclude) specific paths from caching?

Another question would be, if this feature breaks with multilanguage URLs (/en/admin/.*)?
And it's a bit dangerous that typically Drupal doesn't use regex for such paths and starts paths with a "/". Perhaps we should point this out more verbose, if it can't be changed technically?

Besides this exclusion, what's especially needed in my case, seems "scope" = /app, am I right?

This doesn't make the other points and questions here less important, but makes the scope configuration and working functionality essential in my case.

Perhaps I got things wrong here. Let's discuss and finish this @Grevil.

I think you are misunderstanding this field.

"urls_to_exclude" has NOTHING to do with the manifest.json. This is a service worker setting and defines the urls to exclude from caching.

But your point is clear, this should definitely still work for multilingual sites AND for sites having their pwa in a different directory.

Since we are currently using regex to validate whether a URL should be cached or not, there isn't a straight forward way to include (aka !exclude) paths in "urls_to_exclude".

I think instead of using regex here, we should instead require the https://github.com/sindresorhus/globby js library and use that to include / exclude paths with a ".gitignore" like syntax.