I believe the official name is "surtitles", as they appear above the stage. (One small advantage for the cheap, high seats with easy view of surtitles.) Those are pretty standard these days in the big theaters. Don't be fooled that the Germans and Italians are understanding all the lyrics. With the long, drawn out notes and flourishes from the orchestra drowning out the singers, many/most of the native listeners are following along because they already know the lyrics. Ditto for the few operas in English. I have had surtitles for Nixon in China, and definitely needed them.