Examine source code of Textarea Expander

{
  "manifest_version": 2,
  "name": "Textarea Expander",
  "version": "1.0",
  "description": "Expand all textareas on a page to show their full content at page load.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{36c9af15-fbde-4624-a458-1713851e4cb1}"
    }
  }
}