1. Go to takeout.google.com
  2. Click on "Deselect All"
  3. (view screenshot) (screenshot of the page)
  4. Then scroll all the way down, make sure YouTube is selected,
    and then click on "Multiple Formats"
  5. (view screenshot) (screenshot of the page)
  6. Scroll to the bottom and change "history" to the JSON format and press "OK"
  7. (view screenshot) (screenshot of the page)
  8. Then click on "All YouTube data included"
    Deselect all and make sure ONLY history is checked
  9. (view screenshot) (screenshot of the page)
  10. Press "OK", then the blue "Next Step" button.
    Change the max file size to 4GB.
  11. Wait for an email in your inbox that will let you know when it's ready
    It'll really only take 5 minutes.
  12. Download the zip file from the link sent to your inbox,
    and finally locate the watch-history.json file
    ./Takeout/YouTube and YouTube Music/history/watch-history.json
I've got it!