Examine source code of Silence Window

{
  "manifest_version": 2,
  "name": "Silence Window",
  "version": "3.0",
  "description": "Use Ctrl+Shift+U or click the icon to mute a window",
  "icons": {
    "32": "icons/silence_32.png",
    "64": "icons/silence_64.png"
  },
  "applications": {
    "gecko": {
      "id": "{27519780-f9c4-4ea2-9f0c-9132f5fdd75d}"
    }
  },
  "permissions": [
    "storage"
  ],
  "commands": {
    "toggle-feature": {
      "suggested_key": {
        "default": "Ctrl+Shift+U"
      },
      "description": "Silence window"
    }
  },
  "browser_action": {
    "default_icon": "icons/noSilence_64.png",
    "default_title": "Silence Window"
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true,
    "open_in_tab": true
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}