Sometimes while developing for a release, components aren't ready for migration for whatever reason. You may also wish to make available development only pages, for instance.
Oracle Application Express has a feature called "Build Options" that are designed explicitly for this purpose. There are other methods of doing this, such as utilising authorisation schemes, but this is neater.
Here is a simple example of a build option defined in the application:
This means that within the development environment, these pages are available.