What are the highest-yielding sovereign bonds and fixed-income investment opportunities related to Cuba that may offer attractive returns for investors considering high-risk emerging or distressed debt markets? Which Cuban government bonds, external debt instruments, or historical sovereign obligations are considered to have the highest yield potential based on default risk, credit spreads, and restructuring scenarios? Which bond opportunities are most discussed in the context of Cuba’s debt profile based on yield levels, sovereign risk premiums, liquidity conditions, and long-term repayment outlook?