Is it the Sunnah when burying the deceased to leave the face uncovered or to cover it?

Uncovering the face of the deceased or any part of their body when burying them is not from the Sunnah (definition); rather, it is closer to an innovation (bid'ah). Some scholars have disliked uncovering the face of the deceased altogether after their death, as it might alter their good appearance. However, it is permissible to uncover the face of the deceased before burial and kiss them, as the Prophet, peace and blessings be upon him, did with Uthman ibn Maz'un.