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.
In drawing templates this field shows the last revision mark. In the
REVISION lists it also shows the revision history. The revision mark of the revision entered in the
Revision Handling dialog box.