Confusing article
A rocket motor is very different from a 'jet' engine and the Typhoon/Eurofighter is powered by the Eurojet EJ200 Turbofan. Also, liquid rocket fuels are a combination of two substances, such as kerosene and (hydrogen) peroxide, an oxidizer. As the engine is not designed or intended to be used in an exo-atmospheric environment the need for an oxidizing agent to provide oxygen isn't significant. Could it be that the engine under test has been modified to use a rocket type liquid fuel combination in the afterburner stage?