In case anyone's curious, I found the code behind this feature. The service's description and configuration intent can be set during a service binding, if and only if the caller is running as SYSTEM.
http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/2.2.1_r1/com/android/server/am/ActivityManagerService.java#11651
int clientLabel = 0;
PendingIntent clientIntent = null;
if (callerApp.info.uid == Process.SYSTEM_UID) {
// Hacky kind of thing -- allow system stuff to tell us
// what they are, so we can report this elsewhere for
// others to know why certain services are running.
try {
clientIntent = (PendingIntent)service.getParcelableExtra(
Intent.EXTRA_CLIENT_INTENT);
} catch (RuntimeException e) {
}
if (clientIntent != null) {
clientLabel = service.getIntExtra(Intent.EXTRA_CLIENT_LABEL, 0);
if (clientLabel != 0) {
// There are no useful extras in the intent, trash them.
// System code calling with this stuff just needs to know
// this will happen.
service = service.cloneFilter();
}
}
}
This code was moved at some point, but still exists in KitKat, unchanged.
http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.4.2_r1/com/android/server/am/ActiveServices.java#665