There are many language negotations bundled into core but there is one missing, detecting the language through a browser's cookie.
Instead of having contributed modules for that thing, I propose to include it into core.
To get it working, the patch in the #1314384: Remember the provider that selected the language for later use → must be applied. It will be soon included in D8.
There is a new negotiation row in the language detection system page.
No API changes.
Closed: outdated
9.5
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Think with 12 years of inactivity this method of language detection isn't sought after.
If still a valid feature request please reopen updating issue summary.
Also tried researching if this is a preferred method and didn't find any recent articles, everything was 10+ years old.
Thanks!