This is a request for a function that allowed a keyframe’s peg properties to be copied and automatically updated based on what is done on another keyframe. It would be similar to what we do on drawings, but with the properties of the peg.
That would be super useful for creating and editing cycles.
If you copy (Ctrl+C / Ctrl+V) a peg that already has keyframes (and that way functions assigned to the keyframable attributes) the new peg will have the same functions assigned to it as the originial.
That means that when you create a keyframe on the original peg the copied one will get the same keyframe and vice versa.
Is that what you are looking for?