Examine source code of Highlight Fix for Trello

{
  "manifest_version": 2,
  "name": "Highlight Fix for Trello",
  "version": "1.0",
  "description": "Makes highlighted text in Trello visible again.",
  "icons": {
    "128": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://trello.com/*"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{16ceb6f7-f503-48cd-8edd-44b0708c4a93}"
    }
  }
}