Examine source code of Ticketmatic

{
  "manifest_version": 2,
  "name": "Ticketmatic",
  "version": "1.0.14resigned1",
  "description": "Ticketmatic integration",
  "icons": {
    "48": "icons/tm-icon-48.png",
    "128": "icons/tm-icon-128.png",
    "256": "icons/tm-icon-256.png",
    "768": "icons/tm-icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.ticketmatic.com/*"
      ],
      "js": [
        "inject.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "nativeMessaging"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{94541c5b-469f-4458-be01-16f332ba87ae}"
    }
  }
}