label="[value]"
This attribute appears optional. If blank, this has the equivalent effect of causing the visible attribute to be set off. This is the mechanism originally used (pre v3.0.5) to make 'untitled' links have no caption on Map view arrows. Note that this attribute can be used to give a different screen caption than the default of the name value, though in general you shouldn't not need to do this - there is no advantage (at present!).
Example:
<link name="*untitled" label="" color="#000000" visible="o" style="0" />
<link name="XYZ" label="something else" color="#000000" visible="1" style="0"/>
<link name="agree" color="#000000" visible="1" style="0"/>
