From Galaxytool wiki
Current Version: 4.6 Galaxytool Changelog Download as zip or tar.gz
Galaxytool Language Files
of 10-27-2010 Language Files Changelog Download as zip or tar.gz
Mozilla Firefox Extension - Galaxyplugin
Current version (for all redesign universes) 2.4.3 Toolbar Changelog Download Mozilla
Current Version (for Ogame v0.84) 2.1.11 Toolbar Changelog Download xpi
Legality-this plugin is 100% legal.
Modifications from other developer
To develop your own modification for the galaxytool you need the permission from the Galaxytool author. This is to ensure a secure Galaxytool including its modifications which might create security holes.