This is a template attribute. Template attributes can be used in filtering, or to retrieve data from the model to use in drawings and reports. For example, when you create a report, Tekla Structures replaces the attributes added in the report template with the corresponding object property values.
This attribute gets the value entered in the Checked By box on the Status tab in the user-defined attributes dialog box of the part or in the assembly properties dialog box. Also shows the value that you have entered in the Checked By field in the Revision Handling dialog box.