: It follows the Structured Field Values format, using a question mark followed by a boolean: ?0 : Desktop (False). ?1 : Mobile (True).
: Serve expansive, multi-column designs rather than single-column mobile stacks.
: Include interactive elements that rely on mouse-hover actions, which don't exist on touchscreens. sec,ch,ua,mobile:,?0
For more technical implementation details, you can refer to the official documentation on MDN Web Docs. Sec-CH-UA-Mobile header - HTTP - MDN Web Docs
When a server identifies a user as desktop-based via this header, you should deliver: : It follows the Structured Field Values format,
: Enable mega-menus and secondary sidebars that require significant screen real estate. Context and Syntax
The ?0 value is a boolean indicator where 0 means "false" (not a mobile device). If you are "drafting proper content" based on this header, your server-side logic should prioritize and features. Content Strategy for ?0 (Desktop) : Include interactive elements that rely on mouse-hover
: It is part of the Privacy Sandbox initiative to reduce the information leaked by traditional "User-Agent" strings.