Files robots.txt and favicon.ico do not exist in Elxis 4.0 release but we recommend you to put them there in order to avoid error notices by robots and browsers asking them.
User-agent: *Disallow: /includes/libraries
User-agent: *Disallow: /secretadmin
Or, better, be empty (there is no need to disallow something in Elxis 4.x as everything is locked)