The Source area of the Attribute Editor contains information related to the attribute for the selected field on the form.

Attribute Name	Attribute name as it is defined for the Source. For new fields added to the form the attribute name will be the same as the Label name assigned to the field. For existing fields the Label will inherit the name of the source attribute when the attribute is added as a field to the form. If that Label name is changed the attribute name will be changed as well to match it.
Data Type	The Data Type of the attribute as it is defined in the Source, e.g., Text, Number, Media, Video, etc.
Size	Size of the data as defined in the Source, e.g, Varchar (10)