The Continuous Call Curves are use to determine the frequency of function calling when a key is held down.

You can find the default curve in /UmgInputManager/Curves/CF_BaseInputFrequency, if you open this asset you’ll see a curve composed by nodes

if you hover a node with the mouse cursor you’ll see that a tooltip will popup

it contains the axes of the curve, Time and Value.

• Time: specify the time passed in seconds since the key was pressed, so at this node after 2 seconds that the key was pressed the Value will be 0,2
• Value: is the frequency itself expressed in seconds, in this case 0,2 means that the function will be called every 0,2 seconds a this point (or 5 times per second)