ctrl.json

{
  "name": "Massdrop CTRL",
  "vendorId": "0x04d8",
  "productId": "0xeed2",
  "lighting": "none",
  "matrix": {"rows": 11, "cols": 8},
  "layouts": {
    "keymap": [
      [{"c":"#777777"},"0,0",{"x":1,"c":"#cccccc"},"0,1","0,2","0,3","0,4",{"x":0.5,"c":"#aaaaaa"},"0,5","0,6","0,7","6,0",{"x":0.5,"c":"#cccccc"},"6,1","6,2","6,3","6,4",{"x":0.25,"c":"#aaaaaa"},"6,5","6,6","6,7"],
      [{"y":0.5,"c":"#cccccc"},"1,0","1,1","1,2","1,3","1,4","1,5","1,6","1,7","7,0","7,1","7,2","7,3","7,4",{"c":"#aaaaaa","w":2},"7,5",{"x":0.25},"7,6","7,7","9,7"],
      [{"w":1.5},"2,0",{"c":"#cccccc"},"2,1","2,2","2,3","2,4","2,5","2,6","2,7","8,0","8,1","8,2","8,3","8,4",{"w":1.5},"8,5",{"x":0.25,"c":"#aaaaaa"},"8,6","8,7","9,6"],
      [{"w":1.75},"3,0",{"c":"#cccccc"},"3,1","3,2","3,3","3,4","3,5","3,6","3,7","9,0","9,1","9,2","9,3",{"c":"#777777","w":2.25},"9,4"],
      [{"c":"#aaaaaa","w":2.25},"4,0",{"c":"#cccccc"},"4,1","4,2","4,3","4,4","4,5","4,6","4,7","10,0","10,1","10,2",{"c":"#aaaaaa","w":2.75},"10,3",{"x":1.25,"c":"#777777"},"9,5"],
      [{"c":"#aaaaaa","w":1.25},"5,0",{"w":1.25},"5,1",{"w":1.25},"5,2",{"c":"#cccccc","w":6.25},"5,3",{"c":"#aaaaaa","w":1.25},"5,4",{"w":1.25},"5,5",{"w":1.25},"5,6",{"w":1.25},"5,7",{"x":0.25,"c":"#777777"},"10,4","10,5","10,6"]
    ]
  }
}

I got VIA working on the CTRL thanks to all of the contributors awesome work using the following steps:
(see Massdrop/mdloader#49 for the full discussion)

Patch & Build mdloader

1. Clone https://github.com/Massdrop/mdloader
2. Apply Massdrop/mdloader#49 (https://github.com/Massdrop/mdloader/pull/49.patch) - git am 49.patch
3. Apply Massdrop/mdloader#50 (https://github.com/Massdrop/mdloader/pull/50.patch) - git am 50.patch
4. Build patched mdloader with VS2019
5. Activate / set SmartEEPROM to the current implementation (I was using Massdrop/mdloader#16 before) - mdloader.exe --first --smarteep --forceeep --restart

Patch & Build QMK

1. Clone https://github.com/qmk/qmk_firmware
2. Apply qmk/qmk_firmware#6068 (https://github.com/qmk/qmk_firmware/pull/6068.patch) - git am 6068.patch
3. Add a keymap for VIA and applied the EEPROM_SIZE 1024 mentioned here Massdrop/mdloader#49 (comment) (board would not start with the default calculated value) - you can see my commit at kaeltis/qmk_firmware@c90b2b8 or qmk/qmk_firmware@master...kaeltis:master
4. Build qmk with qmk setup kaeltis/qmk_firmware (or your fork) and qmk compile -kb massdrop/ctrl -km via
5. Flash qmk using mdloader.exe --first --download massdrop_ctrl_via.bin --restart

Use VIA

1. Start VIA
2. Click on File -> Import Keymap
3. Import the json file from here: https://gist.github.com/kaeltis/c81ffbe79d7e8a92218dd8a610db39b7

After that you should be able to reassign keys in VIA, lighting currently does not work due to the custom implementation (afaik).

For reference, here's the layout on KLE if anyone needs it:
http://www.keyboard-layout-editor.com/#/gists/df6c13bb95885418bf5c6c8f280e93aa