Microsoft just released a tool for Windows Embedded Standard 7 (but also interesting for the upcoming POSReady 7) called
CBS Package Inspector.

The tool allows opening and inspecting Feature Packages, Updates, etc. These packages are delivered as CBS packages (Component-Based Servicing) and can be applied via DISM.

Why is this tool useful?

• See the whole content of a package including possible sub-packages
• Check the dependencies of packages
• See which files and registry entries are created or modified

To download the tool and for more information please visit the Microsoft Code Gallery page.