Select debug app
This setting relaxes a few restrictions on the ability for developers to pause execution of a chosen app while debugging.
When an app is selected using this option, debugging of this app via an attached debugger is allowed to pause execution of the app at a breakpoint for a long period of time without issuing a warning, and enables the Wait for debugger option allowing the execution of this app to pause after launching until the debugger is able to attach to it.
According to Android documentation, this setting is not required to be set in order to use a debugger to debug Android apps, unless using the above features.
This setting has no benefits for non-developers and should be left disabled.