Examine source code of GPTPromptMaster

{
  "manifest_version": 3,
  "name": "GPTPromptMaster",
  "version": "1.0.5",
  "description": "Create custom Pre and Postprompts for ChatGPT",
  "action": {
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "GPTPromptMaster@mcfrank.com"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://chat.openai.com/*"
      ],
      "css": [
        "content.css"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  },
  "icons": {
    "16": "icons/icon_16.png",
    "32": "icons/icon_32.png",
    "48": "icons/icon_48.png",
    "128": "icons/icon_128.png"
  }
}