Examine source code of canvasRepopulator

{
  "manifest_version": 2,
  "name": "canvasRepopulator",
  "version": "2.0",
  "description": "Re-enters the answers you choose from the last time you took a quiz.",
  "icons": {
    "48": "umd.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.instructure.com/courses/*/quizzes/*/take"
      ],
      "js": [
        "script.js"
      ]
    }
  ]
}