Sec,ch,ua:,""microsoft,edge"";v=""107"",,""chromium"";v=""107"",,""not=a?brand"";v=""24"" Apr 2026

: 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.

The most "interesting" part of this header is the Not=A?Brand segment, which is a deliberate feature of the . : Historically, websites would break if they didn't

: Identifies the primary brand and major version. "perfect" list of brands

: The "grease" brand used to ensure servers handle arbitrary brand strings correctly. : Historically, websites would break if they didn't

: The Not=A?Brand entry is a "fake" brand added to the browser's identification list. Its purpose is to "grease" the ecosystem—forcing web developers to write code that can handle unexpected or unknown browser names.

: Identifies the underlying engine (Edge is built on Chromium).