Examine source code of Easy File Saver Extension

{
  "name": "Halo File saver",
  "author": "Sourabh Tejawat & Akhilesh Joshi",
  "version": "1.4",
  "description": "For saving updated and orignal files.",
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "pages/popup.html",
    "default_icon": "icons/icon128.png",
    "default_title": "Easy File Saver Extension"
  },
  "externally_connectable": {
    "matches": [
      "https://shopstar2-test.halo.com/preview/edittemplates.admin",
      "https://shopstar-clone.halo.com/preview/edittemplates.admin",
      "https://www.mybrandmall.com/preview/edittemplates.admin"
    ]
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "activeTab",
    "alarms",
    "background",
    "bookmarks",
    "browsingData",
    "clipboardRead",
    "clipboardWrite",
    "contentSettings",
    "contextMenus",
    "cookies",
    "debugger",
    "declarativeContent",
    "desktopCapture",
    "downloads",
    "fontSettings",
    "gcm",
    "geolocation",
    "history",
    "idle",
    "management",
    "nativeMessaging",
    "notifications",
    "pageCapture",
    "power",
    "printerProvider",
    "privacy",
    "proxy",
    "sessions",
    "storage",
    "system.cpu",
    "system.display",
    "system.memory",
    "system.storage",
    "tabCapture",
    "tabs",
    "topSites",
    "tts",
    "ttsEngine",
    "unlimitedStorage",
    "webNavigation",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "run_at": "document_idle",
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "js/jquery-3.4.1.min.js",
        "js/script.js",
        "js/inject.js"
      ]
    }
  ],
  "update_url": "http://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "content_security_policy": "script-src 'self' https://www.google-analytics.com; object-src 'self'",
  "web_accessible_resources": [
    "*.js",
    "*.css"
  ]
}