For now: https://xfce.org/ fails with 404 Not Found Error. Cached from search engine url (for example https://www.xfce.org/download/) fails on certificate: www.xfce.org uses an invalid security certificate. The certificate is only valid for the following names: wiki.xfce.org, xfce.org (Error code: ssl_error_bad_cert_domain) With HTTP Strict Transport Security (HSTS), so I can't add an exception.
Closing (Certificate are now managed with let's encrypt, no more invalid/expired certificates).