What happened?

The GUI loads its locale preference list from the browser's settings through the /svc/lang API endpoint. The HTTP header value is however treated as being specified in reducing preference order, with the q= quality values being discarded.

It should be sorted by decreasing q value (where omission means q=1), according to the specification at https://httpwg.org/specs/rfc9110.html#field.accept-language

Different browsers may send the HTTP header value with different ordering. Therefore the sorting should be done in the backend API service.

Syncthing version

v1.27.10

Platform & operating system

n/a

Browser version

Header varies by browser, but service should sort the result

Relevant log output

No response