SourceEntityInterface should be in migrate_drupal and also the entityTypeId method isn't needed. Patch attached to prove the latter.
The last submitted patch, le.patch, failed testing.
zhuber queued le.patch for re-testing.
SourceEntityInterface has been removed. https://www.drupal.org/node/2558851
Comments
Comment #4
phenaproximaSourceEntityInterface has been removed. https://www.drupal.org/node/2558851