This is the best evidence yet that this is indeed an April Fool's prank.
Whois is also less than certain. Domain redirects to a generic parking site.
With respect to the USPTO, I believe only patent applications can be filed confidentially. FCC applications can also be filed confidentially. But I believe trademark applications are published immediately upon filing, because the essence of a trademark is use in commerce. You don't need to file a trademark application with the USPTO to be protected by trademark law, but it is an important element of notice, which is relevant when determining certain aspects of infringement claims.