What happens if I forfeit or flee from a “duel to the death”?

[Porwazkazbek-westfall]

Continuing the discussion from WoW Classic Era 1.14.4 Development Notes:

@Kaivax

In an upcoming PTR update, we intend to implement a very punishing deserter-style debuff for players that flee an honorable Duel to the Death, in order to prevent exploits and non-participation in an agreed-upon duel.

Wondering what the penalty will be.