Examine source code of Audio FX

{
  "manifest_version": 3,
  "name": "Audio FX",
  "version": "0.8.1",
  "description": "Slowed + reverb, nightcore, lofi, 8D audio, karaoke and EQ for any audio in any browser tab.",
  "browser_specific_settings": {
    "gecko": {
      "id": "audiofx@kurnatengimejl.dev",
      "strict_min_version": "121.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "activeTab",
    "scripting",
    "downloads"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Alt+A",
        "mac": "Alt+A"
      },
      "description": "Open Audio FX popup"
    }
  },
  "background": {
    "scripts": [
      "ExtPay.js",
      "background.js"
    ]
  },
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "Audio FX",
    "default_icon": {
      "16": "icons/16.png",
      "32": "icons/32.png",
      "48": "icons/48.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ]
}