: Historically, websites would break if they didn't recognize a browser. By including a randomized string like Not=A?Brand , browsers ensure that servers don't rely on a fixed, "perfect" list of brands, which prevents future-proofing issues.
: Identifies the underlying engine (Edge is built on Chromium). : Historically, websites would break if they didn't
: The "grease" brand used to ensure servers handle arbitrary brand strings correctly. "perfect" list of brands
The string you've shared is a header, typically used by browsers like Microsoft Edge to identify themselves to web servers without revealing the excessive detail often found in traditional User-Agent strings. : Historically, websites would break if they didn't
The most "interesting" part of this header is the Not=A?Brand segment, which is a deliberate feature of the .