What are Bulgarian Stock Exchange (BSE) ETNs?

Could you elaborate on what Bulgarian Stock Exchange (BSE) ETNs are? I'm curious to understand their structure, purpose, and how they operate within the financial market. Are these ETNs specifically designed to track the performance of the Bulgarian stock market? Do they provide investors with exposure to Bulgarian stocks in a more convenient and liquid manner? What are the key risks and considerations for investors looking to purchase BSE ETNs? Your insights would be greatly appreciated.