I know that the proper server response header should be
503 Service Unavailable, to let the search bots know that they shouldn't index the pages like Update in progress and Server maintenance. But what is the proper content for the robots.txt on these pages?
In my setup the maintenance page is not a sub-page of a site. I have the maintenance page as a dedicated website in server configuration. I add bindings to it whenever I put the original site offline. Would you recommend empty robots.txt,
User-agent: * Disallow: / or the same robots.txt as the original website?