Examine source code of hPass

{
  "manifest_version": 2,
  "name": "hPass",
  "description": "HMAC-based password derivation tool",
  "version": "1.3resigned1",
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "index.html",
    "default_title": "Open hPass"
  },
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{996d3a03-f9fa-44b8-a48d-252d2174d68a}"
    }
  }
}