Setting CustomConfig=Foo in a Target.cs file will cause it to overlay config files from Project/Config/Custom/Foo on top of the defaults, allowing easy override of things like OSS settings to support multiple stores
In development, -CustomConfig=foo can be specified in both C++ and C# to enable the same functionality, which can be used to select between multiple different stage/deploy configurations in a build script
#rb josh.adams, ben.marsh
[CL 17017130 by ben zeigler in ue5-main branch]
cc4f7aa8d1