Sorry for gravedigging but I feel need to react - that answer is not really correct.
As far as I know, in TheDude, "link full" can be found in
setting->apperance->link and it sets color which link will turn into, once it reaches predefined maximum speed. Each link can have this speed defined either based on link type or manually. Default color of link is black, as it goes towards maximum speed, it will turn to default red color or to color which you set in "link full".
shortly said - the "link full" sets the color of fully utilized link.
example (instead of default red, utilized link goes to purple color):
2018-11-21_1616.png
You do not have the required permissions to view the files attached to this post.