What is meant by "two rak'ahs before al-Ghadah," and when exactly is their time?

"Al-Ghadah" refers to the Fajr prayer, and the two rak'ahs before it are the two rak'ahs of Fajr. They are mentioned in hadiths, such as the hadith narrated by Aisha (may Allah be pleased with her): "He (the Prophet) never used to leave four rak'ahs before Dhuhr and two rak'ahs before al-Ghadah." And these two rak'ahs are better than the world and all that it contains. Their time is from the beginning of the Fajr prayer time until the Fajr prayer itself, meaning between the second Fajr adhan and the iqamah. The Prophet (peace be upon him) used to pray them in his home when Fajr appeared and the muezzin made the adhan.