xpize & Open Source
XPize (4.7 and earlier) is based of a simple file patching engine that uses ResHacker scripts to modify system files.
The sources to these are here:
XPize Installer System
The patching engine used by XPize 4.7 and earlier
Last built 2007-01-23. File size is 10.32MB with an MD5 hash of 87fefabd08974a9fee87806686579c8a
XPize 4.6
These are the sources to the unreleased 4.6 version. The final 4.7 version is only marginally different.
Last built 2007-03-25. File size is 36.77MB with an MD5 hash of 7b8a3f92c23789fd21b78391486ecb47
The Anolis Project
xpize 5 is built with a new patching engine called Anolis which is a non-commercial open-source application suite and software library written in C#.
The Anolis project is shared by xpize's sister project: Vize (UI enhancements for Windows Vista). The project is managed on CodePlex.
The Anolis Project has not produced any releases yet. We anticipate replacing the XPize Installer System entirely when we reach 1.0.
Anolis is licensed under a custom license which is analog to Creative Commons' Attribution-NonCommercial-ShareAlike license.