This is Piero's "Wing Ring" with "Copy Scale Constraints":
My "Piero Wing Rig" can be found here.
@theluthier and @waylow Could you please test it 😉?
I'm not familiar with what stage this is in course but the wings look like they are working correctly.
Although, from the images I can see that there is some parenting that leads to the root bone (which should be the way that it works), however, in the file nothing is parented to the root bone.
Did you accidentally clear this? If so, just make sure the root of each relevant section is parented to the Root bone.
But other than that it is looking correct.
Thank you, @waylow 😀! I've downloadad the file from Dropbox and opened it with Blender 2.90 which I use for editing my Piero. The "Relationship Lines" to the "Root Bone" are displayed. Did you maybe turn off their visibility in the "Overlays"?
The wings are now completely rigged with all "Constraints" and "Drivers" in place. Next stop is the completion of the left leg's rig here.
@waylow The "Relationship Lines" are running from the "Control Points" of the "MCH_armSpline.L" curve to the origin of the "Armature" named "rig" since these points have "Hook Modifiers" which connect them to bones of the "rig".
After having moved the "Root Bone" away from the "Armature's" origin:
The "Hook Modifiers" on "MCH_armSpline.L" :