Examine source code of simple emoji keyboard

{
  "manifest_version": 2,
  "name": "Emoji Keyboard",
  "version": "1.0.0",
  "description": "A simple emoji keyboard popup to copy or insert emojis into the current page. Click an emoji to copy it; use 'Insert' to place it into the active input/textarea/contenteditable field.",
  "permissions": [
    "activeTab",
    "storage",
    "clipboardWrite"
  ],
  "browser_action": {
    "default_title": "Emoji Keyboard",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{b186d3ff-7112-46b7-9391-b9a7e343e7f1}"
    }
  }
}