Figure out why WebfingerLocalizedTest fails

Okay, my hypothesis is correct. Something to do with path-based negotiation.

Is the test still valid using query parameter negotiation?

The non-localized test still passes and the empty query array is the same URL assertion as previously.

The test failure is probably related to 📌 An existing .well-known directory (as for Let's Encrypt) can prevent ActivityPub module's webfinger from working Active in that documentation would help to clarify that web server configuration may be necessary to allow Drupal to handle ".well-known/webfinger" both at the root and potentially in a sub-directory. Probably out-of-scope for this issue?

Cool, and yes, makes sense. Merged, thanks!