Examine source code of 1000% Sound Volume

{
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  "manifest_version": 2,
  "default_locale": "en",
  "name": "__MSG_appName__",
  "description": "__MSG_shortDesc__",
  "icons": {
    "16": "icons/icon_16.png",
    "32": "icons/icon_32.png",
    "48": "icons/icon_48.png",
    "128": "icons/icon_128.png"
  },
  "browser_action": {
    "default_title": "__MSG_appName__",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon_16.png",
      "32": "icons/icon_32.png",
      "48": "icons/icon_48.png",
      "128": "icons/icon_128.png"
    }
  },
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_end",
      "js": [
        "src/contentScript/index.js"
      ]
    }
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "background": {
    "persistent": true,
    "scripts": [
      "src/background/index.js"
    ]
  },
  "web_accessible_resources": [
    "*.*"
  ],
  "permissions": [
    "<all_urls>",
    "tabs",
    "storage"
  ],
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+6"
      }
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{eb5fac1b-31a8-43d9-9599-fc921316b1ff}",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}