Examine source code of Roll20 Made Easlier

{
  "name": "Roll20 Made Easlier",
  "description": "(Indev) General tools for roll 20, in one browser plugin.",
  "version": "1.0.0",
  "manifest_version": 2,
  "permissions": [
    "*://app.roll20.net/editor/"
  ],
  "icons": {
    "16": "/icons/easlier16.png",
    "32": "/icons/easlier32.png",
    "48": "/icons/easlier48.png",
    "128": "/icons/easlier128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "/icons/easlier16.png",
      "32": "/icons/easlier32.png",
      "48": "/icons/easlier48.png",
      "128": "/icons/easlier128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://app.roll20.net/editor/"
      ],
      "js": [
        "src/turn-timer/index.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{295cbd7b-c1f7-43dd-86a1-c36cd9eca068}"
    }
  }
}