Generally, the question stands as what steps need to be done in order to send 2-nd generation managed package for security review.
Current conditions:
I have developed 2-nd generation managed package on standalone dev org.
After that client has created their partner salesforce account and linked both namespace and developer dev orgs to that partner account.
here on "Publishing" tab showing, that there are no packages on that orgs.
Am I missing something? Is it possible to publish 2-nd generation managed package for security review? If no, what do I need to do in order to send it to security review ?
Update. Winter '20 made Second Generation Managed Packages GA. Go ahead and publish them!