Examine source code of background image

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "View background image",
  "version": "1.0.4resigned1",
  "description": "Adds a \"open background image in new tab\" menu item. Finds closest element to the clicked area that has a background image.",
  "permissions": [
    "contextMenus",
    "<all_urls>"
  ],
  "background": {
    "persistent": false,
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "icons/16.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ee9507aa-5b54-4548-a8b1-f1840b6d5c26}"
    }
  }
}