Did he recite in them Surah Fatiha (only)?
Sahih Muslim Book 6, Hadith 114
← Previous Hadith 'A'isha reported that the Messenger of Allah (ﷺ) used to observe two (supererogatory) rak'ahs in between the call to prayer and the Iqama of the dawn prayer.

Sahih Muslim Book 6, Hadith 113 Next Hadith → When it was dawn, the Messenger of Allah (ﷺ) observed two rak'ahs, and I would say: Does he recite only the opening chapter of the Qur'an in it?

Sahih Muslim Book 6, Hadith 115