Maps game controller physical buttonsto virtual outputs that can be tuned for an optimal in-sim experience. Outputs can be virtual axes, or vitual buttons. A typical use would be mapping your Sptifire Mk IX elevator trim wheel to a single virutal axis that you use in sim. What's more, you can tune the sensitivity of the axis to aproximate the correct turn rate of the trim wheel in sim.
If you rename a mapping to an empty string (i.e. delete the name) then the mapping is disabled and you can't delete it, or add in a name.