If you have certain shifts you do not want any employees to see you can create a new position for his purpose and then set the shift to that position and then never publish that particular position. Partial publishing allows you to keep certain positions/shifts only for managers to view.
If you regularly want to have shifts not published you might want to create a “position group” that includes all positions you normally publish and excludes the hidden position. Then before clicking Publish just choose that Position Group in the Positions dropdown.
keep a “deleted” shift on the schedule create manager schedule