Malik related to me from Yahya ibn Said that A'isha, the wife of the Prophet ﷺ said, "The Messenger of Allah ﷺ used to pray the two rakas of the dawn (fajr) so quickly that I would say to myself 'Has he recited the umm al-Qur'an or not?' "
أَنَّ عَائِشَةَ زَوْجَ النَّبِيِّ ﷺ قَالَتْ إِنْ كَانَ رَسُولُ اللَّهِ ﷺ لَيُخَفِّفُ رَكْعَتَىِ الْفَجْرِ حَتَّى إِنِّي لأَقُولُ أَقَرَأَ بِأُمِّ الْقُرْآنِ أَمْ لاَ
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] 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