From the website FAQs:
Our new action filing will include people in the following situations:
An I-129F has been approved, but is stuck at the National Visa Center
The case is at the consulate, but an interview has not been scheduled
The interview has been scheduled and cancelled at least once
The interview has happened, but the case is stuck in administrative processing
The K-1 visa was issued, but because of travel restrictions, the K-1 beneficiary was unable to travel before the visa expired and the consulate has not reissued the visa.