The drush command 'migrate-manifest' could not be found Not sure if it's a dupe issue, couldn't find it. Just trying to run an upgrade in drush8 and get:

The drush command 'migrate-manifest' could not be found.  Run drush cache-clear drush to clear the commandfile cache if you have installed new extensions.

Tried with previous 8.* version and got the same problem.
answering my own question, this is now in the contrib module migrate-manifest: