It will likely email your foreign fiancé.
In our case I kept my foreign fiancee’s email out of the process for as long as possible to inject as much determinism and consistency as possible (whiled keeping her CC’ed on emails).
Fortunately, they did not force a switch to her email until after the interview was scheduled.
Some and perhaps most embassies provide no insight into what is actually going on. Like a black hole. So the couple needs to be proactive with letting the embassy know that that keen interest in a visa continues.
Remember that unlike approved I-130s, approved I-129Fs expire. As long as the foreign fiancé actively seeks a visa before I-129F expires, and does so after it expires through no fault of the petitioner or beneficiary, the embassy should extend the petition.