Exposes the old user levels system, which fixes the WordPress author drop-down bug when users don’t have a role with one of the assigned levels.
Fixes the missing author WordPress bug
User levels were abandoned in WordPress version 2.1. We’ve long since moved on to roles and capabilities. However, the core WordPress author drop-down on the edit posts screen requires user levels to work properly.
This is problematic when creating custom roles. So, users with a custom role often don’t have an associated level. Thus, these users don’t appear in the author drop-down, even if they have permission to edit a post.