In the skill specialization trees (e.g. when you’re trying to specialize into Warpath and allocate points to it), you can hover over each node to see a tooltip of its description.
However, within that tooltip there are often embedded links like “…blah blah Echoes blah blah…”. It looks like you should be able to then hover over or click on “Echoes” for more info on what that means. But as soon as you move the mouse, the parent tooltip closes so there’s no way to actually get to the word “Echoes”. (I still don’t know what it means).