DefaultAssignment= location
When you add related objects using the "Upload new" button located in the "Related objects" window in the object edit interface, the "Location" dropdown in the upload dialog allows you to choose where the uploaded file should be placed in the node tree. If "Automatic" is selected, then the location specified by the "DefaultAssignment" setting will be used.
The default value of this setting is "root", which means that related objects will be placed directly under the "Content" top level node. The following options can be also used:
Note that this setting alone doesn't allow you to specify multiple locations for related objects that are being uploaded. Multiple locations can however be specified using the "ClassSpecificAssignment" directive; making it possible to set up rules for different types of objects that override the value of the "DefaultAssignment" directive. If the current user doesn't have sufficient "create" privileges under the locations specified using the "ClassSpecificAssignment" , the system will fallback to and use the value of the "DefaultAssignment" directive.
DefaultAssignment=media
Newly created (uploaded) related objects will (by default) be placed under the "Media" top level node. This will be the case unless specified otherwise by the "ClassSpecificAssignment" directive or if the current user doesn't have sufficient "create" privileges at the locations specified by the "ClassSpecificAssignment" directive.