In order to fix it, all what to do is edit
$ doas nvim /var/www/.../<drupal-dir>/web/sites/default/settings.php $ # settings.php is read-only by default
When <fqdn> is "sub.orroot.domain" in actual, add lines like this:
/** * Trusted host configuration. * * Drupal core can use the Symfony trusted host mechanism to prevent HTTP Host * header spoofing. ... * For example: * @code * $settings['trusted_host_patterns'] = [ * '^www\.example\.com$', * ]; * @endcode * will allow the site to only run from www.example.com. ... */ + $settings['trusted_host_patterns'] = [ + '^sub\.orroot\.domain$', + ];
Refreshing "Status report" page will bring comfortable result that all tests are passed.