Examine source code of SoundFixer

{
  "manifest_version": 2,
  "name": "SoundFixer",
  "version": "1.4.3",
  "description": "Lets you fix annoying sound problems in YouTube videos and such. Like audio in one channel only, too quiet or too loud",
  "browser_specific_settings": {
    "gecko": {
      "id": "{4564fda5-aaf9-45f6-84b6-e9c2b086a849}"
    }
  },
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "permissions": [
    "activeTab",
    "webNavigation"
  ],
  "browser_action": {
    "default_icon": "icon.svg",
    "default_title": "SoundFixer",
    "default_popup": "popup.html",
    "theme_icons": [
      {
        "dark": "icon.svg",
        "light": "icon-inv.svg",
        "size": 64
      },
      {
        "dark": "icon.svg",
        "light": "icon-inv.svg",
        "size": 48
      },
      {
        "dark": "icon.svg",
        "light": "icon-inv.svg",
        "size": 32
      },
      {
        "dark": "icon.svg",
        "light": "icon-inv.svg",
        "size": 16
      }
    ],
    "browser_style": true
  }
}