The OP has a valid point. He has a very legitimate question about the legalities involved. Many posters here think Conor is bound to the UFC contract everywhere in the world. That's not the way the law works.
Conor and Floyd can fight in any country where the presiding judge would not grant an injunction to stop the fight. China, Russia, Ireland, etc there are a lot of countries that have more pressing matters than stopping Conor McGregor from boxing. The UFC does have a case after the fight.
Since Floyd is not under contract with the UFC, they have no recourse against him.
Conor could be sued but it wouldn't be worth it. for the UFC . Going to court vs their most popular fighter is the last thing the UFC wants. Let Conor make his money and hope he comes back for fights against GSP, Nate, Nick, Aldo.
The new UFC management would be idiots to try to gain a few million dollars by suing Conor.