Examine source code of Open Last Download

{
  "name": "Open Last Download",
  "version": "1.0.2resigned1",
  "description": "Opens the last downloaded file",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "utils.js",
      "main-last-download.js"
    ]
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "F1"
      },
      "description": "Open Last Download"
    }
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "icons/last-download-16.png"
    },
    "default_title": "Open Last Download"
  },
  "permissions": [
    "downloads",
    "downloads.open"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{756c67cd-5c67-4850-9213-c45c18e254f3}"
    }
  }
}