Examine source code of a11y Twitter

{
  "manifest_version": 2,
  "name": "a11y Twitter",
  "description": "Accessible reminders for Twitter.",
  "version": "1.2.2",
  "browser_action": {
    "default_icon": {
      "16": "icon16.979acb2f.png",
      "48": "icon64.6d78cba9.png",
      "128": "icon128.426fb704.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.twitter.com/*"
      ],
      "run_at": "document_idle",
      "js": [
        "contentScript.149e215f.js"
      ],
      "css": []
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{09660116-28b8-47c8-9dfc-1defdffcaaeb}"
    }
  }
}