Examine source code of Safe Web

{
  "manifest_version": 3,
  "name": "Safe Web",
  "description": "Web filter / blocker for porn, malicious and adult sites.",
  "icons": {
    "16": "puzzle16.png",
    "48": "puzzle48.png",
    "128": "safeWeb128.png"
  },
  "version": "2.1.1.0",
  "author": "George Zotos",
  "action": {
    "default_icon": "safeWeb48.png",
    "default_title": "Safe Web",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "storage",
    "tabs",
    "activeTab",
    "webNavigation"
  ],
  "host_permissions": [
    "https://www.extendbrowser.com/*",
    "https://z.api.safedns.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4b92896c-e84d-4578-92bb-67f57e2dc7e2}"
    }
  }
}