Card Numbers for Trello

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Card Numbers for Trello",
  "version": "2.0.0",
  "description": "Show the card numbers on trello.com for easier communication in a team",
  "content_scripts": [
    {
      "matches": [
        "https://trello.com/*"
      ],
      "css": [
        "override.css"
      ],
      "all_frames": true
    }
  ]
}