Shared deck download removes all non-ASCII characters from filename

[dae]

The deck at https://ankiweb.net/shared/info/1521800111 1 (chosen for its name only) is called:
Русский - Турецкий Rusça-Türkçe kelimeler(слов) 407
_-__Rusa-Trke_kelimeler_407.apkg

Probable solution:

Content-Disposition: attachment; filename="fallback.txt"; filename*=UTF-8''%E4%B8%AD%E6%96%87.txt

When the AnkiWeb code was originally written, filename* had not yet been introduced.

Originally reported on https://forums.ankiweb.net/t/shared-deck-download-removes-all-non-ascii-characters/47617