Hello @jim brown
The name of the configuration file is internal to the .NET Framework and can not be changed. What I've done in the past and will not suit many other developer needs is to avoid using app.config and instead using a .json file which circumvents app.config while at the same time places you in complete control.
I have a sample project showing both conventional and json configuration.
https://github.com/karenpayneoregon/visual-basic-getting-started/tree/master/MySettingsAlternate