The request refers to setting a language preference within a browser's Accept-Language header.
: A typical optimized header for a German speaker who also knows English might look like: en-US,en;q=0.9,de-DE;q=0.8 . 0.9,de-DE
The value de-DE;q=0.9 tells a website that is your preferred language, with a "quality value" (q) of 0.9. This value ranges from 0 to 1, where higher numbers indicate a stronger preference. How to use this feature The request refers to setting a language preference