Just as QNX C/C++ projects have build variants, container projects have build configurations. Each configuration can be distinct from other configurations in the same container. For example, you could have two separate configurations, say Development and Released, in your top-level container. The Development configuration would build the Development configuration of any included container projects as well as the appropriate build variant for any projects. The Released configuration would be identical except that it would build the Released variants of projects.
The default configuration is the first configuration that was created when the container project was created.
To create a build configuration for a container: