These Ruling(s) have not been confirmed as applicable to the TCG.[Notes 1]
In place of declaring a FULL card name, a precise description of a card's stats, appearance, and/or effects, is considered acceptable so long as both players are in clear agreement over which card is being described.
The cards revealed by the effect of "Ma'at" are verified by both players. Furthermore, if the declared card(s) are among the revealed cards, the declared card(s) are added to the hand, and the remaining cards are sent to the Graveyard.
The effect that modifies the ATK of "Ma'at" lasts while it remains face-up on the field. Also, if the effect of "Ma'at" is activated once again during the next Main Phase, the ATK value obtained in the previous turn is lost, and the ATK becomes the new value obtained by this effect.
↑Konami Judge Program Rulings are considered unverified, as their source(s) are not publicly viewable. They are not confirmed as applicable to the TCG until they have been officially published by Konami.
↑Konami FAQ: As for the effect of "Ma'at" that makes its ATK become the amount of cards added to your hand by that effect x 1000, how long does it last? Also, if the effect of Ma'at is activated once again during the next Main Phase, what does its ATK become?