Please add the language code xsu to the list of language codes supported for monolingual text values.
Usage example: native label (P1705): Sanöma
(on https://www.wikidata.org/wiki/Q251728 where at the moment, the name in original language is in Brazilian Portuguese...)
IETF code: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry
Type: language
Subtag: xsu
Description: Sanumá
Added: 2009-07-29