Examine source code of Caps Lock Notifier

{
  "manifest_version": 2,
  "name": "Caps Lock Notifier",
  "version": "1.1.1resigned1",
  "description": "Add an icon to password fields to indicate whether caps lock is on.",
  "developer": {
    "name": "Nick Barry"
  },
  "homepage_url": "https://github.com/itsnickbarry/caps-lock-notifier",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "all_frames": true,
      "js": [
        "caps_lock_notifier.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e994877b-8e2e-4583-aa18-cbe2c5c9198d}"
    }
  }
}