When you build a GeneXus app, the .Net Generator produces the web.config file which gets deployed. I want to add some custom settings to the web.config file, for example URL rewrite rules, in such a way that they are not lost when the build process happens.
How or where would I do this in GeneXus?
Have you already taken a look at Build Events?
https://wiki.genexus.com/commwiki/servlet/wiki?39474,Build%20Events
You can program something that adds the URL rewrite rules to a web.config file maybe using XMLWriter and then add this program to the Post-build Events so it is executed after every GeneXus Build and the file is kept up to date.