(Update 1/16/23: Multiple reports indicate that the Supermarket/Restaurant addition is no longer working in 2023, meaning it has not been extended again.)
Since May of 2020, Citi has been allowing their Prestige cardholders to use the Citi Prestige $250 travel credit at Supermarkets and Restaurants until the end of 2020. Citi has now announced that this extension of the credit has been extended for the duration of 2022.
The Citi Prestige card is no longer available for new applicants.
Hat tip to VFTW

