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

: For older versions of Edge or Internet Explorer, users have modified the AcceptLanguage key under HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International to force these specific quality values. 0.9,de-DE

: Developers use these strings to test how their applications handle internationalization (i18n) and localization (l10n). The value de-DE;q=0

: By setting a high weight like 0.9, you ensure the site knows exactly which language to prioritize if multiple options are available. : Developers use these strings to test how

: If you are a developer using frameworks like Next.js, you can configure i18n locales to automatically detect these headers and serve the correct language version of your site to the user. Why this is a "Good Feature"

: 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 .