CLDR needs a summary of planned v48 features.

Here's a draft:

1. Full support of well-behaved* MF1 message functionality, as Stable
   • Stabilize remaining MF1.0 function support (:datetime, :date, :time, percent-format)
   • Should support migration of all "well-behaved" MF1 messages
2. Functions that go well beyond MF1
   • Goal is enough new functionality to be worth the effort to migrate infrastructure
3. Develop function description format (machine-readable function data), as ≥Draft
4. Create documentation, especially the user guide & messageformat.dev
   • Should include MF1 migration guide.
   • Both to and from MF1, to aid migration before localization tooling catches up

* "well-behaved" excludes choice format and partial selects, like

• "You have {numBooks, plural, one {# book} other {# books}}" instead of
• "{numBooks, plural, one {You have # book} other {You have # books}}"