private boolean containsPdbSymbolDirsWithFiles(File testDir) {
		File[] possibleLevel1SymbolDirs =
			list(testDir, f -> f.isDirectory() && f.getName().toLowerCase().endsWith(".pdb"));
		for (File dir : possibleLevel1SymbolDirs) {
			if (list(dir, f -> f.isDirectory() &&
				SymbolFileInfo.fromSubdirectoryPath("doesntmatter", f.getName()) != null &&
				new File(f, dir.getName()).isFile()).length > 0) {
				Msg.debug(this, "Detected symbol file directory: " + dir);
				return true;
			}
		}
		return false;
	}
Non-task monitor variant of {@link #isValid(TaskMonitor)}.

@return boolean true if this is a valid symbol store
Ghidra/Features/PDB/src/main/java/pdb/symbolserver/LocalSymbolStore.java