For some functions AutoCAD Electrical adds invisible information to a block insert or even to a specific attribute. This invisible data is called Xdata. To add or modify this invisible data, AutoCAD Electrical provides an Xdata editor. You can also change the Xdata on a block to a block attribute.
The existing name and value are shown in the edit boxes allowing you to edit them.
If the selected block or attribute does not carry any Xdata, the list box indicates it.