Examine source code of Page Draw & Doodle

{
  "manifest_version": 2,
  "name": "Page Draw & Doodle",
  "version": "1.1",
  "description": "Page Draw & Doodle transforms any webpage into an interactive canvas to draw and annotate on.",
  "permissions": [
    "storage",
    "contextMenus",
    "tabs",
    "activeTab",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_title": "Page Draw & Doodle",
    "default_icon": "icon.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ],
      "css": [
        "menu.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "commands": {
    "toggle-draw-menu": {
      "suggested_key": {
        "default": "Alt+A"
      },
      "description": "Toggle draw menu"
    },
    "undo": {
      "suggested_key": {
        "default": "Ctrl+Z"
      },
      "description": "Undo last stroke"
    },
    "redo": {
      "suggested_key": {
        "default": "Ctrl+Y"
      },
      "description": "Redo last undone stroke"
    },
    "clear": {
      "suggested_key": {
        "default": "Alt+C"
      },
      "description": "Clear all strokes"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e4da4cf0-3f65-4f29-89bd-36691582d217}"
    }
  }
}