The documentation portal is undergoing maintenance. During this period, you can't create any new user credentials. If you do, you'll need to recreate the user credential after the maintenance period ends.
Effective in version 10.4.0, when you import a resource with the same name as an existing physical data object, the Developer tool allows you to choose how to resolve the conflict. You can choose to create an object with a different name, reuse the existing object, or replace the resource for the existing object.
Previously, the Developer tool failed the table import and did not attempt to import any subsequent tables.