The language-switch trail ping read <html lang> before the view
transition applied the swap, so it reported the previous language (and
read pings never update trail-item languages server-side): multi-
language visits recorded as single-language trails and the analytics
flag combining had nothing to show. The switch ping now passes the
picked tag explicitly.
Language negotiation no longer prefers the article's original language
anywhere in the Accept-Language list — nearly every browser lists
English as a fallback, so translations were almost never served. The
first servable header language now wins, the original counting only in
its natural position.
LeoVasanko
867132f26b