discusses documenting the current situation, this ticket proposes another solution.

• We should pivot to using BCP47 based data everywhere.

• We should rename `root` to `und` (the path is cleared by the sandbox change).

• We should rename any variant files to, for example, `en-US-u-va-posix.xml` ( edit: That is, if no change is proposed by )

• We might note that the `<identity>…<variant>` tag is kept for compatiblity, but we might consider an `<identity><bcp47>…</bcp47></identity>` tag for bcp47

• We might want to produce "old" style (to use the terminology of the docs) LDML output as an alternate format, to ease consumption. We might need to do this perpetually, for compatibility.