Examine source code of Send To Things

{
  "manifest_version": 2,
  "name": "Send To Things",
  "description": "Send the current tab to Things",
  "version": "1.2.1",
  "applications": {
    "gecko": {
      "id": "send-to-things@mozilla.kewis.ch"
    }
  },
  "icons": {
    "256": "images/things.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true
  },
  "browser_action": {
    "default_icon": "images/things.png",
    "default_title": "Send To Things",
    "browser_style": false
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+S"
      },
      "description": "Send the current tab to Things"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}