@Override
	public synchronized int startTransaction(String description) {
		if (manager != null) {
			throw new UnsupportedOperationException(
				"Built-in datatype manager may not be modified");
		}
		return super.startTransaction(description);
	}
Returns shared instance of built-in data type manager.
@return the manager
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/BuiltInDataTypeManager.java