Examine source code of Collapsed Mastodon

{
  "manifest_version": 2,
  "name": "Collapsed Mastodon",
  "version": "0.9.1",
  "icons": {
    "48": "icons/48.png"
  },
  "description": "Collapses the main column of Mastodon for a cleaner view.\nMakes writing toots/searches easier by displaying a small container.",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "js/main.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html"
  },
  "permissions": [
    "storage"
  ]
}