Examine source code of trello-full-desc

{
  "manifest_version": 2,
  "name": "trello-full-desc",
  "version": "1.0",
  "description": "always expand to full description in trello",
  "content_scripts": [
    {
      "matches": [
        "https://trello.com/*"
      ],
      "js": [
        "expand.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{953a4b49-6ca4-440a-8418-2434d2d47568}"
    }
  }
}