Examine source code of DevObserver

{
  "name": "DevObserver",
  "description": "Stay tuned with the latest developer news, articles, tutorials, releases, fun and much more.",
  "version": "1.2.1",
  "manifest_version": 2,
  "homepage_url": "https://devobserver.com",
  "content_security_policy": "script-src object-src 'self'",
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.devobserver.com/*"
      ]
    }
  ],
  "browser_action": {
    "default_title": "DevObserver"
  },
  "icons": {
    "16": "icons/dev-observer-16.png",
    "32": "icons/dev-observer-32.png",
    "48": "icons/dev-observer-48.png",
    "96": "icons/dev-observer-96.png",
    "128": "icons/dev-observer-128.png",
    "256": "icons/dev-observer-256.png",
    "512": "icons/dev-observer-512.png"
  },
  "web_accessible_resources": [
    "index.html"
  ],
  "permissions": [
    "*://*.devobserver.com/*",
    "*://devobserver.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{aee9c76c-7b0c-406b-bc05-fcd8e2bca394}"
    }
  }
}