Wireless Markup Language
From Just Solve the File Format Problem
Wireless Markup Language (WML) is an HTML-variant markup language as part of the Wireless Application Protocol, an attempt to reinvent the Web for the bandwidth, CPU, and memory limitations of wireless networks and mobile devices.[1] WAP existed around the turn of the millennium, and flopped within a few years.
Curiously, the official site's hub page for WAP specifications links to password-protected documents. However, a slightly older copy can be found by search engine.