I've looked all over and haven't found an explaination for a lepton (besides the subatomic particle).

For instance, the art.ini file says that the firing location for the Kirov's bombs is Forward, Lateral, Height: -50,0,-140 in leptons. I went to the bomb's location in Will's editor and it's approximately XYZ: 30,0,68. X:30 and makes sense since it's the center of a 59-voxel-wide unit, which would correspond to the Lateral value of 0, so perhaps Leptons measure from the center-out. But, Forward:-50 & Z:68 and Height:-140 & Y:0 don't seem to be related to their counterparts. Y:0 of course makes sense if the vehicle is firing from its base, but how does that convert to -140 leptons in a 59-unit-high voxel?