When an object is governed by a room, its permission set is ruled by the room, and only the room’s members can access it. While a governed object may be linked to other locations in a repository, only members of the room that governs the object can access it. A room governs anything created within or imported into it, except for another room.
When an object becomes governed (is either created in or copied to the room or a governed folder), the room’s default permissions are applied to the object. If the room’s permission set is changed, all permission sets for governed objects are changed accordingly.
In the Room column of a list (indicated by the 
icon), objects that belong to rooms are distinguished by one of the following icons, which are their governing indicators:
means the item belongs to (or is governed by) the same room as the current folder.
means the object belongs to a different room.
Clicking a governing indicator opens the room’s home page. Click the header icon to sort a list of objects according to whether they belong to the same room, a different room, or no room.
If you show all versions in a folder, each version of an object that is visible to you has its own governing indicator since different versions may belong to different rooms.
You can turn off the Room column by using Display Setting preferences for columns.