Examine source code of Text Tools

{
  "manifest_version": 2,
  "name": "Text Tools",
  "short_name": "Text Tools",
  "version": "1.0.23",
  "description": "Handy text tools a click away",
  "icons": {
    "16": "icon_16.png",
    "48": "icon_48.png",
    "128": "icon_128.png"
  },
  "browser_action": {
    "default_title": "Text tools",
    "default_popup": "firefox.html",
    "default_icon": "icon_19.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{24def25c-e637-473b-94b5-837e07d70b24}"
    }
  }
}