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)
When a server identifies a user as desktop-based via this header, you should deliver: sec,ch,ua,mobile:,?0
: It is a "low-entropy" hint, meaning browsers like Chrome send it by default on every secure (HTTPS) request without the server needing to ask for it. : Deliver larger images or background videos that
: Deliver larger images or background videos that might be too heavy for mobile data connections. : Include interactive elements that rely on mouse-hover
: It follows the Structured Field Values format, using a question mark followed by a boolean: ?0 : Desktop (False). ?1 : Mobile (True).
: Include interactive elements that rely on mouse-hover actions, which don't exist on touchscreens.
: Enable mega-menus and secondary sidebars that require significant screen real estate. Context and Syntax