Examine source code of Simple THighlighter

{
  "manifest_version": 2,
  "name": "Text Highlighter",
  "version": "1.0",
  "description": "A simple highlighter extension",
  "icons": {
    "48": "icons/pen.svg"
  },
  "permission": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "Highlight.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{71dcf6a3-ec1a-4c7c-99c7-97a84ce848b2}"
    }
  }
}