Mine

DEFAULT_RECEIVED = Received: ${if def:sender_rcvhost {from $sender_rcvhost }{${if def:sender_ident {from ${quote_local_part:$sender_ident} }}${if def:sender_helo_name {(helo=$sender_helo_name) }}}}by $primary_hostname ${if def:received_protocol {with $received_protocol}} ${if def:tls_cipher {($tls_cipher) }}(Exim $version_number) ${if def:sender_address {(envelope-from <$sender_address>) }}id $message_exim_id${if def:received_for { for $received_for}}

received_header_text = ${if eq {$sender_host_address}{"127.0.0.1"} {"X-Privacy: masked"}{DEFAULT_RECEIVED}}