The virtual block device template group data type presents the structure in which a group of archived image templates will be presented. The structure consists of a parent template group which contain multiple child template group objects. Each child template group object represents the image template in a particular location. Unless editing/deleting a specific child template group object, it is best to use the parent object.
A virtual block device template group, also known as an image template group, represents an image of a virtual guest instance.