Template talk:Script/Slavonic

Lang
The documentation says:
 * Valid language codes
 * Old Church Slavonic cu or chu (default)
 * Church Slavonic cu or chu (default)

However if I leave the language slot empty, it doesn't emit an HTML lang attribute. Shouldn't it emit lang="cu-Cyrs"? Shouldn't it emit the -Cyrs script tag for all languages? Test: --Error (talk) 23:57, 25 May 2021 (UTC)