Examine source code of Zendesk Submit Expander

{
  "name": "Zendesk Submit Expander",
  "short_name": "ZSE",
  "version": "2.4.0.0",
  "manifest_version": 2,
  "description": "Takes the ticket submit buttons from the drop-up box in the Zendesk agent view and puts them into a button group instead.",
  "author": "Dominic Shelton",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.zendesk.com/agent/tickets/*"
      ],
      "run_at": "document_start",
      "css": [
        "zendesk-submit-expander.css"
      ],
      "js": [
        "zendesk-submit-expander.js"
      ]
    }
  ]
}