question: private static Map < String , VirtualFile > findSiblings ( @ Nullable VirtualFile directory , Project project , Set < VirtualFile > seen ) { if ( directory == null ) { return Collections . emptyMap ( ) ; } else { if ( seen . contains ( directory ) ) { return findSiblings ( null , project , seen ) ; } seen . add ( directory ) ; VirtualFile settings = directory . findChild ( SdkConstants . FN_SETTINGS_GRADLE ) ; if ( settings == null ) { return findSiblings ( directory . getParent ( ) , project , seen ) ; } else { return GradleModuleImporter . getSubProjects ( settings , project ) ; } } }
target:  Recursively go up the file system tree to find parent project with settings.gradle and then obtain collection of siblings from that file.