Examine source code of Image Toggle

{
  "manifest_version": 2,
  "name": "Image Toggle",
  "version": "1.0",
  "description": "Toggle visibility of all images on the webpage.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    },
    "default_title": "Toggle Images",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{9b34d79f-8d4f-48cc-a632-f6e56e1b0877}"
    }
  }
}