Language Tags and Locale Identifiers for the World Wide Web

2020-10-07: ACTION-2264 Janina to review. Note we want to be sure sign languages are included in all this.
2021-05-05: Janina has read, will file question in their github.
2022-01-12: The issue is around identifying sign languages, which is more of a IANA language tags registry question. We'll put on the RQTF plate for down the road.
2022-01-26: Sign languages are well represented in BCP47, note https://r12a.github.io/app-subtags/.