'not supported any more' message has broken URL

It's not really broken. If it can't find the equivalent page in the latest version, it triggers a search for the path.

See the message:

Sorry, the path ... cannot be matched against any page in this branch. Try searching by one of the components of the path.

The main issue that I see is that the status message is not styled. The classes seem to be ok, so it's the CSS somehow not loading.

The alternative was either to go to the homepage of the supported/preferred branch or to trigger the search.

There is a version of that on 11 though: https://api.drupal.org/api/drupal/core%21modules%21system%21system.token...

Yeah, but it's not under the same path, that's the issue.

We could defo improve the matching, trying to get the object being seen and see if there is the same object in the latest version. Or even explode the URL and try to guess it. eg: https://api.drupal.org/api/drupal/core%21modules%21system%21system.token... would be "system_token_info", and search would find that.