This one looks like and feels like the popular "Microsoft ® Registry Editor" (A.K.A. regedit.exe ), specifically one that comes from Win2k default installation.
It only has one (significative) difference... It will never prompt you with following message box, when started:

"Registry editing has been disabled by your administrator."

This restriction is supposed to save users from themselves. Well, if you've successfully located an override (like mine ), I hope you really know what's you're doing! My regedit clone will ignore administrator's restriction, which consist in the following registry patch:
Then, you may use reg3dit to make all the changes you need (note that on Windows NT/2k/XP & superiors some keys would still give you "Access denied", as such OSes use per-user security policies). For example, you can unpatch that DisableRegistryTools thing and simply turn back to use default regedit.exe

P.S. - reg3dit has nothing to do with the leaked Win2k source!!! I've created it by my own.