Examine source code of Backlinks Checker

{
  "manifest_version": 2,
  "name": "Backlinks Checker",
  "version": "1.0",
  "description": "Checks for backlinks to the current webpage.",
  "icons": {
    "48": "icons/backlinks-48.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/backlinks-48.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{35e7aab6-6530-450a-9bf3-b5ea222b220f}"
    }
  }
}