The topic had me interested
I have a MK11 Frontera 370 (Model 215) which has a ULO box mounted on the frame at the front up under the fuel tank, opposite the horn. I believe it is a 6v Capacitor which perhaps "smooths" the voltage. There are many options for the lighting/ignition, both 6 and 12v. I am lead to believe that LED globes require DC power (battery).
I have both a 214 (250 MK11) which has upgraded 12VAC power (work in progress with lighting) I intend to use a 12v Jump starter as a total loss system to run indicators etc and 12Ac headlight and taillights
The model 215 (MK11 370) has the stock 6v Motoplat ignition system, horn headlight and taillights which all work. I bought a 215 parts bike which has the ULO ( I suspect it as a USA spec bike
best wishes with the project
peter
peter