question: @ Nullable private static PsiFile findFileToOpen ( @ NotNull List < PsiFile > files ) { PsiFile bestFile = null ; FolderConfiguration bestConfig = null ; for ( PsiFile file : files ) { PsiDirectory qualifiedDirectory = file . getParent ( ) ; assert qualifiedDirectory != null : "Resource file's parent directory cannot be null" ; FolderConfiguration config = FolderConfiguration . getConfigForFolder ( qualifiedDirectory . getName ( ) ) ; if ( bestConfig == null || config == null || config . compareTo ( bestConfig ) < 0 ) { bestConfig = config ; bestFile = file ; } } return bestFile ; }
target:  Returns the best configuration of a particular resource given a set of multiple configurations of the same resource. 