The Messenger of Allah (ﷺ) was more particular about observing the supererogatory rak'ahs before the dawn prayer than about observing any of the other supererogatory prayers.
Sunan Abi Dawud Book 5, Hadith 5
← Previous Hadith The Prophet (ﷺ) never omitted four rak'ahs before the noon prayer, and two rak'ahs before the dawn prayer.

Sunan Abi Dawud Book 5, Hadith 4 Next Hadith → 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.

Sunan Abi Dawud Book 5, Hadith 6