A linkType type tag is included for every built-in link type and any user-created ones. If a link type has a link action, then the action's code is stored in an optional child <onLink> tag.
<linkType name="*untitled" label="" visible="1" showLabel="0" color="#000000" colorString="#000000" style="0" />
name. The name used for the linkType in code and type listings.
label. The name use when a link label is shown in maps.
visible. Number, zero or one. '1' is visible, '0' means the link is not drawn on screen.
showLabel. Number, zero or one. '1' is visible, '0' means the link is not drawn on screen.
color. The colour used to draw link lines. Stored as a hash-prefixed six-digit hex code.
colorString. A text string, which must be for a defined named
color. Otherwise the value of 'color' (above) is used.
style. A number. Some form of hash of the state of all the various line style options (not documented).