Examine source code of Image Dimensions Viewer

{
  "manifest_version": 2,
  "name": "Image Dimensions Viewer",
  "version": "1.0",
  "description": "Muestra las dimensiones de las imágenes al pasar el ratón por encima y permite habilitar/deshabilitar por página",
  "permissions": [
    "activeTab",
    "storage",
    "theme"
  ],
  "browser_action": {
    "default_icon": "icon.svg",
    "default_title": "Habilitar/Deshabilitar"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8cab2fbd-a216-4e5e-84fd-5d575ec1c706}"
    }
  }
}