What is this NSIS.Library.RegTool file?

[zanz]

I'm developing a few new installers, and I noticed that in the InstallDir, there's this file generated by NSIS installer:

NSIS.Library.RegTool.v2.{Some GUID}.exe.

At first I thought may be if i reboot my machine, this file will go away (this particular installer requires a reboot each time user installs the product).

Even after a reboot this file remains in the InstallDir. What's the function of this file? Is it safe to use? I tried searching for this file online, but didn't find much help. Thanks!