Examine source code of Scrawly

{
  "manifest_version": 2,
  "name": "Scrawl",
  "description": "Draw on any web page with excalidraw.",
  "version": "0.2.1",
  "background": {
    "persistent": false,
    "scripts": [
      "js/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "js/content.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "/images/icon16.png",
      "32": "/images/icon32.png",
      "48": "/images/icon48.png",
      "128": "/images/icon128.png",
      "300": "/images/icon300.png"
    },
    "default_title": "Scrawl"
  },
  "icons": {
    "16": "/images/icon16.png",
    "32": "/images/icon32.png",
    "48": "/images/icon48.png",
    "128": "/images/icon128.png",
    "300": "/images/icon300.png"
  },
  "permissions": [
    "storage",
    "webNavigation"
  ],
  "web_accessible_resources": [
    "excalidraw-assets/*",
    "excalidraw-assets-dev/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{534e0a54-1bc9-4c1a-bf03-c3f4ea70cc01}"
    }
  }
}