Examine source code of DisappointedMage Toolbar

{
  "manifest_version": 3,
  "name": "DisappointedMage Toolbar",
  "description": "Firefox DevTools extension for Magento debugging. Works with MSP_DevTools module.",
  "version": "1.0.3",
  "browser_specific_settings": {
    "gecko": {
      "id": "disappointedmage-toolbar@disappointed.mage",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "16": "images/icon16x16.png",
    "48": "images/icon48x48.png",
    "128": "images/icon128x128.png"
  },
  "action": {
    "default_icon": "images/icon_off.png",
    "default_title": "DisappointedMage Toolbar",
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "background": {
    "scripts": [
      "js/browser-polyfill.min.js",
      "js/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "js/browser-polyfill.min.js",
        "js/content.js"
      ]
    }
  ],
  "devtools_page": "devtools.html"
}