Examine source code of Better Volume Booster

{
  "manifest_version": 3,
  "name": "Better Volume Booster",
  "version": "1.15.2",
  "description": "Volume booster firefox extension that remembers your choices.",
  "icons": {
    "48": "images/icon-512.png",
    "128": "images/icon-512.png",
    "512": "images/icon-512.png"
  },
  "action": {
    "default_popup": "pages/popup.html"
  },
  "options_ui": {
    "page": "pages/options.html",
    "browser_style": false
  },
  "background": {
    "scripts": [
      "scripts/utils.js",
      "scripts/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "scripts/utils.js",
        "scripts/content.js"
      ],
      "run_at": "document_start",
      "all_frames": true,
      "match_about_blank": true
    }
  ],
  "optional_permissions": [
    "<all_urls>"
  ],
  "permissions": [
    "declarativeNetRequestWithHostAccess",
    "storage",
    "scripting",
    "cookies",
    "contextMenus"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "VolumeBoosterWithoutDementia@zWolfrost.github.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}