Examine source code of Clearhive

{
  "manifest_version": 2,
  "name": "Clearhive",
  "version": "0.2.4resigned1",
  "description": "Click the Clearhive icon in the bottom right corner of Firefox. We'll create a Clearhive email forwarder for the page you're on and copy it to the clipboard. As easy as it gets.",
  "homepage_url": "https://clearhive.com",
  "icons": {
    "32": "icon.png"
  },
  "permissions": [
    "activeTab",
    "clipboardWrite",
    "https://*.clearhive.com/*"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Clearhive",
    "default_popup": "data/panel_content.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "jid1-2a9reiUa7ithtQ@jetpack"
    }
  }
}