The context is the negative yielding treasuries in Europe (Germany). Here is a quote I found on the matter:
Why would a zero-coupon perpetuity not be worth exactly zero? Because its nominal value adds to the stock of debt of the issuer and so it is an option on recovery value - Michael Jezek, Deutsche Bank
This has a bit too much jargon for me to understand clearly, even after multi-tabbing investopedia.
Can someone explain this concept to me in a very simple way, as if I were your grandma?