+When building its own certificate chain, an OpenSSL client/server will
+try to fill in missing certificates from B<CAfile>/B<CApath>, if the
+certificate chain was not explicitely specified (see
+L<SSL_CTX_add_extra_chain_cert(3)|SSL_CTX_add_extra_chain_cert(3)>,
+L<SSL_CTX_use_certificate(3)|SSL_CTX_use_certificate(3)>.
+