Microsoft Toolkit, formerly known as "Office 2010 Toolkit" or "EZ-Activator," is an unofficial program created to activate pirated copies of Microsoft software. Version 2.5.1 is an older release of this tool, historically targeting specific versions of operating systems and productivity suites.
If you are looking for open-source activation scripts, the community generally considers MAS (Microsoft Activation Scripts) Microsoft Toolkit 2.5.1 Download