Examine source code of FBCharts

{
  "name": "FBCharts",
  "description": "Supercharge fbref.com player pages with football radar charts",
  "version": "1.0.4",
  "manifest_version": 3,
  "action": {
    "default_popup": "popup.html",
    "default_title": "Football Radar Charts"
  },
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "run_at": "document_idle",
      "css": [
        "after.css"
      ],
      "js": [
        "after.js"
      ],
      "matches": [
        "http://*.fbref.com/*",
        "https://*.fbref.com/*"
      ]
    }
  ],
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "chartsfb@gmail.com",
      "strict_min_version": "109.0"
    }
  }
}