private static void copyFilesFromPreviousVersion(File subSettingsDir, String dirName,
			FileFilter filter) {
		File previousDir = GenericRunInfo.getPreviousApplicationSettingsDir(dirName, filter);
		if (previousDir != null) {
			try {
				FileUtilities.copyDir(previousDir, subSettingsDir, filter, TaskMonitor.DUMMY);
			}
			catch (CancelledException | IOException e) {
				// don't care - just means we couldn't copy old files to new ghidra version
			}
		}
	}
Returns a list of files in a setting subdirectory that have the given file extension,
copying files from older versions of Ghidra if the settings dir is not yet established.
@param dirName the name of the settings subdirectory.
@param fileExtension the file name suffix
@return a list of files in a setting sub directory that have the given file extension
Ghidra/Framework/Generic/src/main/java/ghidra/framework/Application.java