Examine source code of Alt Text Display

{
  "name": "Alt Text Display",
  "description": "Add a context menu to images to show their URL and alt text",
  "version": "0.1",
  "permissions": [
    "contextMenus",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "alt-text-display.css"
      ],
      "js": [
        "alt-text-display.js"
      ]
    }
  ],
  "browser_action": {
    "default_title": "Add Alt Text Display to Image Context Menu"
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "manifest_version": 2
}