Examine source code of Tune Shifter

{
  "manifest_version": 3,
  "name": "Tune Shifter",
  "version": "1.0.0",
  "author": "Afonso Coutinho",
  "description": "Adjust playback speed, volume, and add reverb effects to any audio or video on the current web page.",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_popup": "popup/index.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    },
    "default_title": "Tune Shifter - Click to adjust audio/video settings"
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "oms-tune-shifter@extension",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}