Examine source code of Matomo Helper

{
  "name": "Matomo Helper",
  "version": "0.4.6",
  "description": "Extends Matomo and Matomo Tag Manager",
  "permissions": [
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "mt.css"
      ],
      "js": [
        "mt.js"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    "mt-helper.js"
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "icons": {
    "128": "mt-h.png"
  },
  "manifest_version": 2
}