Examine source code of Dnote

{
  "name": "Dnote",
  "version": "2.0.0",
  "description": "Capture your microlessons without leaving the browser.",
  "applications": {
    "gecko": {
      "id": "sung@dnote.io",
      "strict_min_version": "42.0"
    }
  },
  "icons": {
    "16": "images/iconx16.png",
    "48": "images/iconx48.png",
    "128": "images/iconx128.png"
  },
  "manifest_version": 2,
  "browser_action": {
    "default_icon": {
      "16": "images/iconx16.png",
      "32": "images/iconx32.png"
    },
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": []
  },
  "content_scripts": [],
  "permissions": [
    "storage"
  ],
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+D",
        "linux": "Ctrl+Shift+V",
        "mac": "MacCtrl+D"
      }
    }
  }
}