I have done custom parts both device library and footprint library, if you already have a part that is close, you just use that one, rename it and modify and save.wanted to change the TO-92 to TO-92 wide I couldn't figure out how to do that, maybe it's not possible. This is on KiCad 5.1.9.
by Duane Benson
by Jake Hertz
by Duane Benson