Left layout of YMDK 75% SP84 (aka wheatfield/split75 and mt/split75) http://www.keyboard-layout-editor.com/#/gists/c32946fa4b6e3d9fec0e4d1c67cbd649

sp84_left.kbd.json

[
  {
    "name": "sp84.left"
  },
  [
    {
      "x": 2.25,
      "a": 6
    },
    "Esc",
    "F1",
    "F2",
    "F3",
    "F4",
    "F5",
    "F6"
  ],
  [
    {
      "a": 7
    },
    "",
    "",
    {
      "x": 0.25,
      "a": 4
    },
    "~\n`",
    "!\n1",
    "@\n2",
    "#\n3",
    "$\n4",
    "%\n5",
    "^\n6"
  ],
  [
    {
      "a": 7
    },
    "",
    "",
    {
      "x": 0.25,
      "a": 4,
      "w": 1.5
    },
    "Tab",
    "Q",
    "W",
    "E",
    "R",
    "T"
  ],
  [
    {
      "a": 7
    },
    "",
    "",
    {
      "x": 0.25,
      "a": 4,
      "w": 1.75
    },
    "Caps Lock",
    "A",
    "S",
    "D",
    "F",
    "G"
  ],
  [
    {
      "a": 7
    },
    "",
    "",
    {
      "x": 0.25,
      "a": 4,
      "w": 2.25
    },
    "Shift",
    "Z",
    "X",
    "C",
    "V",
    "B"
  ],
  [
    {
      "a": 7
    },
    "",
    "",
    {
      "x": 0.25,
      "a": 4,
      "w": 1.25
    },
    "Fn",
    {
      "w": 1.25
    },
    "Ctrl",
    {
      "w": 1.25
    },
    "Alt",
    "Super",
    {
      "a": 7,
      "w": 2
    },
    ""
  ]
]