When you add/edit a course in your portal and move to the Advanced settings (1) you can see two options:
- Show on catalog (2) and
- Show on main catalog (3)
These two options are meaningful when you have assigned your course to a branch.
So you can then decide if you want it to be visible only to the branch course catalog or both to the branch and the main catalog.
If you select the first option (Show on catalog) then the course will be visible only to the users that are members of the specific branch.
If you select the second option as well, the course will be visible to the users that don't belong to any branch.
In essence, the main catalog refers to the catalog that is visible by the users that are not members of any branch, while the catalog refers to the branch course catalog, in case that the course is assigned to a branch.
Note: If your course is not assigned to any branch, then each of these options will make the course visible to main course catalog.