This will change the method of Module installation for the development branches. It provides three options, as shown in the following screenshot:

By default, it is set to Install only my modules. This option will install all of your custom modules and their dependent modules in the new development branches. Only automated test cases are performed for these modules. The second option is Full installation. This option will install all of the modules and perform automated test cases for all of those modules. The final option is to Install a list of modules. In this option, you will need to pass a list of comma-separated modules, such as sales, purchases, and my_library. This option will install the given modules and their dependencies.

This setting only applies to development builds. Staging builds duplicate the production build, so they will have the same modules that are installed in the production branch and perform test cases for modules that have an updated version manifest.