Examine source code of Close Tabs Hotkeys

{
  "manifest_version": 2,
  "name": "Close Tabs Hotkeys",
  "version": "1.0.1",
  "description": "Adds keyboard shortcuts 'Close Other Tabs ',  'Close Tabs to Left ' and 'Close Tabs to Right'.",
  "background": {
    "scripts": [
      "close-tabs.js"
    ]
  },
  "commands": {
    "close-other-tabs": {
      "suggested_key": {
        "default": "Alt+O"
      },
      "description": "Close Other Tabs"
    },
    "close-left-tabs": {
      "suggested_key": {
        "default": "Alt+L"
      },
      "description": "Close Tabs to Left"
    },
    "close-right-tabs": {
      "suggested_key": {
        "default": "Alt+R"
      },
      "description": "Close Tabs to Right"
    }
  },
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{052f1b4f-f125-436f-ab3e-b9a4e13555a0}"
    }
  }
}