Entity revision IDs are now prefixed by `drupal_internal__` to be future compatible with JSON APIs planned revision support

attributes.<revision_id> (typically vid) is now automatically aliased to attributes.drupal_internal__<revision_id> to signal to users that it's only useful in use cases that have tight Drupal couplings.

This is being done to improve consistency, prevent confusion and be forward compatible with how JSON API will handle revisioning in the near future. While JSON API does not support revisions today, a proposal has been finalized in #2992833: Add a version negotiation to revisionable resource types. Revision IDs will not be the primary mechanism for navigating revisions. Instead, clients will be best served by following links already present in the response document.