Examine source code of Image Switcher

{
  "manifest_version": 2,
  "name": "Image Switcher",
  "version": "1.0",
  "description": "Show or hide all images on the current page with one click.",
  "browser_action": {
    "default_title": "Image Switcher",
    "default_icon": {
      "64": "icon64.png",
      "128": "icon128.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{319bcb6a-e222-4887-9ffc-f5fdadbc692c}",
      "strict_min_version": "111.0"
    }
  }
}