Examine source code of Right pane remover

{
  "manifest_version": 2,
  "name": "Right pane remover",
  "version": "1.1",
  "description": "This addons removes the right pane from w3schools.com for best.",
  "content_scripts": [
    {
      "matches": [
        "https://www.w3schools.com/*"
      ],
      "js": [
        "removeRightPane.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{7da7860f-224b-41ad-bc15-1edea0bc0f10}"
    }
  }
}