Did he recite in them Surah Fatiha (only)?  

أَنَّهَا كَانَتْ تَقُولُ كَانَ رَسُولُ اللَّهِ ﷺ يُصَلِّي رَكْعَتَىِ الْفَجْرِ فَيُخَفِّفُ حَتَّى إِنِّي أَقُولُ هَلْ قَرَأَ فِيهِمَا بِأُمِّ الْقُرْآنِ  

"I would see the Messenger of Allah ﷺ praying two rak'ahs of Fajr and making them so brief that I said: 'Did he recite the Umm Al-Kitab in them?'"  

إِنْ كُنْتُ لأَرَى رَسُولَ اللَّهِ ﷺ يُصَلِّي رَكْعَتَىِ الْفَجْرِ فَيُخَفِّفُهُمَا حَتَّى أَقُولَ أَقَرَأَ فِيهِمَا بِأُمِّ الْكِتَابِ  

The Prophet ﷺ would pray two rak'ahs before the dawn prayer lightly so much so that I would say: Did he recite Surah al-Fatihah in them.  

كَانَ النَّبِيُّ ﷺ يُخَفِّفُ الرَّكْعَتَيْنِ قَبْلَ صَلاَةِ الْفَجْرِ حَتَّى إِنِّي لأَقُولُ هَلْ قَرَأَ فِيهِمَا بِأُمِّ الْقُرْآنِ  

[Machine] The Messenger of Allah ﷺ used to pray two rak'ahs before dawn prayer and he would shorten them to the point that I would doubt whether he recited Al-Fatiha in them or not.  

كَانَ رَسُولُ اللهِ ﷺ يُصَلِّي الرَّكْعَتَيْنِ قَبْلَ الْغَدَاةِ فَيُخَفِّفُهُمَا حَتَّى إِنِّي لَأَشُكُّ أَقَرَأَ فِيهِمَا بِفَاتِحَةِ الْكِتَابِ أَمْ لَا؟  

[Machine] She heard Aisha say, "If the Messenger of Allah ﷺ used to perform the two Rak'ahs before dawn, he would shorten them. I would even ask, 'Did he recite in them the Mother of the Quran?'"  

أَنَّهَا سَمِعَتْ عَائِشَةَ تَقُولُ إِنْ كَانَ رَسُولُ اللهِ ﷺ لَيُصَلِّي الرَّكْعَتَيْنِ اللَّتَيْنِ قَبْلَ الْفَجْرِ فَيُخَفِّفُهُمَا حَتَّى إِنْ كُنْتُ لَأَقُولُ هَلْ قَرَأَ فِيهِمَا بِأُمِّ الْقُرْآنِ  

The Prophet ﷺ would pray two rak'ahs before the dawn prayer lightly so much so that I would say: Did he recite Surah al-Fatihah in them. (Using translation from Abū Dāʾūd 1255)   

«كَانَ النَّبِيُّ ﷺ لَيُصَلِّي رَكْعَتَيِ الْفَجْرِ فَيُخَفِّفُهُمَا حَتَّى إِنِّي لَأَقُولُ هَلْ قَرَأَ فِيهِمَا بِأُمِّ الْقُرْآنِ؟ »  

[Machine] The translation of the passage is: "The Messenger of Allah ﷺ used to shorten the two units of prayer before Fajr."  

كَانَ رَسُولُ اللهِ ﷺ «يُخَفِّفُ الرَّكْعَتَيْنِ قُبَيْلَ الْفَجْرِ»