Are you talking about the application that a lot of developers throw into their applications? If so then it's simple:
Certain, network driven, applications require a server to contain most of the files to hold the application, database, etc....and then the workstation connecting to the server will hold critial files that "drive" locally and connect to the server and then the application runs on the client. These files are mostly app drivers, ODBC drivers, etc. Winpatch allows a developer to select certain files from a server standpoint that get updated within patches and application upgrades. Once selected from the server, when winpatch runs, it will compare files from the server to the client and then if the file size or modify date is newer or different (whatever the developer defines in winpatch) then the application will overwrite the newer files from the server to the client. Very, very helpful!
Hope that helped....