Tesla model X manual: "Opening a Rear Door with No Power
To open the falcon wing doors in the unlikely situation when Model X has no power, carefully remove the speaker grille from the door and pull the mechanical release cable down and towards the front of the vehicle. After the latch is released, manually lift up the door."[2]
[1] https://global.chinadaily.com.cn/a/202602/03/WS69818ec6a310d...
[2] https://www.tesla.com/ownersmanual/modelx/en_us/GUID-AAD769C...