It's the demo site where Service Worker returns a responce with set Content-Disposition header with non ASCII characters ("123---ファイル---💧⚡🔥---xxx.txt") for the requests are performed
on https://alttiri.github.io/content-disposition-by-sw/
to ./xxx-0, ./xxx-1, ./xxx-2 URLs.
Note: Due to Chromium's bug it's not possible to correctly set Binary String (ByteString) as a header value in Service Worker.
Use Desktop Firefox for this demo.