The location would depend on 2 factors, whether the configuration is local to the user or shared with the other developers and if you are using the file based (legacy) or the directory based project format.
- File based project, local configuration:
.iws
file - Directory based project, local configuration:
workspace.xml
file under.idea
directory - File based project, shared configuration:
.ipr
file - Directory based project, shared configuration:
.xml
file underrunConfigurations
subdirectory of.idea
directory or files inside.run
directory in the project root (you can customize the location of the shared configurations in the latest versions).