Ibn Ziyād narrates from Mālik that he said, “The Sunnah is to go out to the open prayer-ground (jabbāna) for the ʿĪd, except for the people of Mecca, who pray in the mosque.”
Al-Fatāwā al-Hindiyya (1/118) states: “Going out to the jabbāna for the ʿĪd prayer is Sunnah, even if the congregational mosque can accommodate all the worshippers; this is the position of the masters, and it is the correct view.”
In al-Mudawwana, transmitted from Mālik (1/171), it is reported that Mālik said: “The two ʿĪd prayers are not to be held in two separate places, nor are they to be prayed in the mosque; rather, the people should go out just as the Prophet ﷺ went out.” Ibn Wahb relates from Yūnus, from Ibn Shihāb, that he said: “The Messenger of Allah ﷺ used to go out to the muṣallā, and the people of the towns followed this practice after him.”
Ibn Qudāma al-Ḥanbalī said in al-Mughnī (2/229–230): “The Sunnah is to perform the ʿĪd prayer in the muṣallā; ʿAlī (may Allah be pleased with him) ordered that …”