Review: Drupal 12 Removing Migrate Drupal and Migrate Drupal UI from Core, with a Migration-Readiness Plan for Drupal 10/11 Teams

Drupal core is drawing a clean boundary for Drupal 12: the general Migrate API stays, but the Drupal 6/7 source migration path shipped as migrate_drupal and the old browser workflow shipped as migrate_drupal_ui are being removed from core. That is no...