Examine source code of SEO Pro Extension

{
  "author": "MarketingSyrup",
  "homepage_url": "https://marketingsyrup.com/",
  "manifest_version": 2,
  "name": "SEO Pro Extension",
  "version": "2.3",
  "icons": {
    "16": "images/icons/ic_seo-pro.png",
    "48": "images/icons/icon-48.png",
    "128": "images/icons/icon-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": "images/icons/ic_seo-pro.png",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "css": [
        "css/inject.css"
      ],
      "js": [
        "js/inject.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "http://*/*",
    "https://*/*",
    "webRequest",
    "webNavigation"
  ],
  "web_accessible_resources": [
    "popup.html"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{438301f8-20a9-4142-9863-f851f57001d7}"
    }
  }
}