Examine source code of EasyBib Toolbar

{
  "manifest_version": 3,
  "name": "EasyBib Toolbar",
  "description": "Cite web sites with one click using the EasyBib Toolbar and receive advice on the credibility of the web site you're citing.",
  "version": "1.0.0",
  "action": {
    "default_popup": "popup.html",
    "default_title": "EasyBib Toolbar"
  },
  "homepage_url": "http://www.easybib.com",
  "icons": {
    "16": "images/icon-16.png",
    "18": "images/icon-18.png",
    "19": "images/icon-19.png",
    "32": "images/icon-32.png",
    "48": "images/icon-48.png",
    "128": "images/icon-128.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "host_permissions": [
    "*://*/*"
  ],
  "update_url": "https://clients2.google.com/service/update2/crx",
  "background": {
    "service_worker": "background.js"
  },
  "content_scripts": [
    {
      "js": [
        "contentScript.js"
      ],
      "matches": [
        "*://*/*"
      ]
    }
  ],
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  },
  "externally_connectable": {
    "matches": [
      "*://*/*"
    ]
  },
  "web_accessible_resources": [
    {
      "resources": [
        "/images/*"
      ],
      "matches": [
        "<all_urls>"
      ]
    },
    {
      "resources": [
        "/popup.html"
      ],
      "matches": [
        "<all_urls>"
      ]
    },
    {
      "resources": [
        "/css/*"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}