...It provides background threading, multiple window management, skinning, file and registry access and much more.
It is also possible to create your own plug-ins.
We have used it successfully to create complex HTML applications, including several security suites and installation wizards.
As an installation wizard tool it is very powerful: download only those files you need and conserve bandwidth. Calculate SHA256 checksums for upgrade. Launch MSIs, modify the registry and much more! Can wrap MSI installations or entirely replace them.