What's the meaning of the orange line?

[bigbigpark]

Here is my settings.

start_pos : 0.0, 0.0, 0.0
middle1 : 5.0, 0.0, 1.5
middle1 : 5.0, 10.0, 3.0
middle1 : 0.0, 10.0, 5.0
goal_pos: 0.0, 0.0, 6.0

I have two questions about the results.

1. The markers with 3-axis(red-green-blue) are representing time-scaled trajectory, but don't they have yaw component? I can see only x,y,z components in Rviz.
   
2. What is the meaning of the orange line?