Examine source code of Pins

{
  "manifest_version": 2,
  "name": "Pins",
  "version": "3.2resigned1",
  "description": "Adds the current tab address to Pins",
  "icons": {
    "48": "icons/webpins_48.png",
    "96": "icons/webpins_96.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "48": "icons/webpins_48.png"
    },
    "default_title": "Add to Pins"
  },
  "background": {
    "scripts": [
      "webpins.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "jid0-GzPbxgM5ecfhXjYrIRoLlkD3Ilk@jetpack"
    }
  }
}