Editors is a reference field for all entities and is related to change tracking. Editors and Editor search the same information, however,the plural version of the field provides convenience/improved readability of some queries.
To find all entities that have been changed by a user e.g. Administrator, Tester1 or Tester2:
Editors IN [Administrator, Tester1, Tester2]
To find all scripts that have been edited by members of a group ( e.g. Tester Managers):
EntityType = Script AND Editors IN MembersOf('Test Managers')