Why do I see the design entity sld_hub:sld_hub_inst in my design?

Description

The sld_hub entity is an interface controller between the JTAG pins on your device and the following Quartus^® II features that use the JTAG pins:

• SignalTap™ II Logic Analyzer
• In-System Memory Content Editor
• Logic Analyzer Interface
• Nios® II JTAG UART
• Nios II On-Chip Debugging (OCD)