Fifth freedom allows an airline to carry revenue traffic between foreign countries as a part of services connecting the airline's own country. It is the right to carry passengers from one's own country to a second country, and from that country to a third country (and so on).
E.g. in real-life, EK DXB-BKK-SYD-CHC, DXB-MXP-JFK, QF SYD-SIN-LHR, BNE-LAX-JFK etc.
The airline could apply for approval from the countries involved, perhaps only a certain amount of seats on a specific sector for passengers between the cities on that sector only.