Examine source code of Senderstack

{
  "icons": {
    "16": "icon16.plasmo.2577fc03.png",
    "32": "icon32.plasmo.d583dc1e.png",
    "48": "icon48.plasmo.e0fcfb1d.png",
    "64": "icon64.plasmo.e6259081.png",
    "128": "icon128.plasmo.96a1ede9.png"
  },
  "manifest_version": 3,
  "action": {
    "default_icon": {
      "16": "icon16.plasmo.2577fc03.png",
      "32": "icon32.plasmo.d583dc1e.png",
      "48": "icon48.plasmo.e0fcfb1d.png",
      "64": "icon64.plasmo.e6259081.png",
      "128": "icon128.plasmo.96a1ede9.png"
    },
    "default_popup": "popup.html"
  },
  "version": "1.2.3",
  "author": "SenderStack",
  "name": "SenderStack - AI Email Reply | Writer",
  "description": "Effortlessly manage your inbox and craft perfect emails in seconds.",
  "background": {
    "scripts": [
      "static/background/index.js"
    ]
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "http://127.0.0.1:8000/?logged_out=true",
        "https://senderstack.com/?logged_out=true"
      ],
      "js": [
        "logout-embed.fa8e3a5d.js"
      ],
      "run_at": "document_start",
      "css": []
    },
    {
      "matches": [
        "http://localhost:8000/dashboard",
        "http://localhost:8000/congratulatory",
        "http://localhost:8000/upgrade",
        "http://127.0.0.1:8000/dashboard",
        "http://127.0.0.1:8000/congratulatory",
        "http://127.0.0.1:8000/upgrade",
        "https://senderstack.com/dashboard",
        "https://senderstack.com/congratulatory",
        "https://senderstack.com/upgrade"
      ],
      "js": [
        "main-site-embed.61d9468f.js"
      ],
      "run_at": "document_start",
      "css": []
    },
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "js": [
        "gmail-reply-button.be3c6f5c.js"
      ],
      "css": []
    },
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "js": [
        "gmail-compose-button.d38eb9a2.js"
      ],
      "css": []
    },
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "js": [
        "GmailSidebar.4d06a273.js"
      ],
      "run_at": "document_start",
      "css": []
    }
  ],
  "host_permissions": [
    "http://localhost/*",
    "https://mail.google.com/*",
    "https://senderstack.com/*",
    "https://accounts.google.com/*",
    "https://www.googleapis.com/*",
    "http://0.0.0.0/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@senderstack.com"
    }
  },
  "web_accessible_resources": [
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "resources": [
        "gmail-reply-button.d9ad3c43.png"
      ]
    },
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "resources": [
        "gmail-reply-button.d9ad3c43.png"
      ]
    },
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "resources": [
        "gmail-reply-button.d9ad3c43.png"
      ]
    }
  ]
}