Examine source code of Ad Replacer by Conway

{
  "manifest_version": 2,
  "name": "Ad Replacer By Conway",
  "version": "1.1.3",
  "description": "Replaces ads with custom ads",
  "browser_specific_settings": {
    "gecko": {
      "id": "adreplacement@example.com",
      "strict_min_version": "58.0"
    }
  },
  "permissions": [
    "activeTab",
    "<all_urls>",
    "storage",
    "contextMenus"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}