The icon should follow the same design as the other icons. having the Parent transformation Icon as that will confuse user thinking its not part of same category
In the blender icon style, top corner circle representing parent, dash for the link, arbitrary oriented gizmo.
the big picture :
a preview :
Belle journée, Jérémie
Icons are not needed here at all, these icons do not add any value here, moreover, they even interfere, well, it’s obvious… Design Resources & Educational Material - #7 by jenkm