Examine source code of HTML 2 Embed

{
  "manifest_version": 2,
  "name": "HTML 2 Embed",
  "version": "1.0.0.3resigned1",
  "description": "Compress your HTML right from your Firefox toolbar",
  "homepage_url": "http://pablodiehl.xyz/api/html2embed/",
  "icons": {
    "48": "img/icons/icon-48.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "img/icons/icon-32.png",
    "default_title": "HTML 2 Embed",
    "default_popup": "popup/h2e.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{158a6dc8-5f15-4866-b67f-f45b50a445ce}"
    }
  }
}