Examine source code of VLR+

{
  "manifest_version": 3,
  "name": "VLR+ Basic",
  "version": "1.71",
  "description": "Customize VLR.gg to your liking! - Basic Version",
  "icons": {
    "16": "vlr16.ico",
    "32": "vlr32.ico",
    "48": "vlr48.ico",
    "128": "vlr128.ico"
  },
  "content_scripts": [
    {
      "css": [
        "vlrplus.css"
      ],
      "js": [
        "jquery.js",
        "script.js",
        "firebase-app.js",
        "firebase-database.js",
        "z.js"
      ],
      "matches": [
        "https://www.vlr.gg/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{30a90cfa-d671-440f-b36f-e68146688ce2}"
    }
  }
}