Examine source code of Twitter Button by Mugiiix

{
  "description": "Twitter button for firefox",
  "manifest_version": 2,
  "name": "Twitter Button by Mugiiix",
  "version": "1.0",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/logo-16.png",
      "32": "icons/logo-32.png",
      "64": "icons/logo-64.png",
      "128": "icons/logo-128.png"
    }
  }
}