Examine source code of Maximum Image Size

{
  "manifest_version": 2,
  "name": "Maximum Image Size",
  "description": "This maximum image size Webextension deals with smaller screens (smaller than your average web designer, anyway) by resizing images so that they fit in your viewport.",
  "version": "1.2resigned1",
  "applications": {
    "gecko": {
      "id": "maximum-image-size@nota-bene.org"
    }
  },
  "permissions": [
    "activeTab"
  ],
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "/injected/maximum-image-size.css"
      ],
      "js": [
        "/injected/maximum-image-size.js"
      ]
    }
  ]
}