Examine source code of URL Blocker

{
  "manifest_version": 2,
  "version": "4.0",
  "name": "URL Blocker",
  "description": "Blocks redirect websites",
  "author": "Moritxius",
  "icons": {
    "48": "icons/border-48.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "data/background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/border-48.png"
    },
    "off_icon": {
      "48": "icons/border-48-off.png"
    },
    "default_title": "URL Block"
  }
}