Here it says Modify the code in app.config, but the snippet gives the file to be downloaded as Web.config. There is an app.config under Ch36Ex03 in the download. Because I am using VCE I created a WCF file in VWD and copied the files over, so I have a web.config under AppControlService.

Should I rename my web.config as app.config? Should I delete all the additional lines of code in the web.config? What is the difference between an app.config and a web.config?

A web.config is used for configuration of Web applications, a app.config is used for configuration of Windows applications. The app.config file is renamed to sampleApp.exe.config during the build with Visual Studio. The web.config stays with this name for Web applications.
In this exercise a Windows application is done to host the WCF service, thus it should be an app.config.

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