Examine source code of ManageBac Pro

{
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "mbpro@jaduastudios.com",
      "strict_min_version": "101.0"
    }
  },
  "name": "ManageBac Pro",
  "version": "1.3.4",
  "description": "A ManageBac upgrade kit for a more pleasant experience",
  "action": {
    "default_popup": "menu.html",
    "default_title": "MBPro App"
  },
  "icons": {
    "16": "resources/icon16.png",
    "32": "resources/icon32.png",
    "48": "resources/icon48.png",
    "128": "resources/icon128.png"
  },
  "permissions": [
    "storage"
  ],
  "options_ui": {
    "page": "options.html"
  },
  "content_scripts": [
    {
      "css": [
        "styles.css"
      ],
      "js": [
        "content.js",
        "themebuilder.js",
        "runner.js"
      ],
      "matches": [
        "*://*.managebac.com/student*",
        "*://*.managebac.com/login*",
        "*://*.managebac.com/teacher/*"
      ]
    }
  ]
}