❓️⬛️

#unknown emoji #missing emoji #placeholder emoji #question mark emoji #tofu character #blank emoji #undefined emoji

❓/❓

#any emoji #unknown emoji #wildcard #missing emoji #which one

❓⬜️

#missing emoji #blank emoji #placeholder emoji #empty slot #unknown emoji #tofu emoji #question mark box

🐱⬜️

#domestic cat #white fur #missing emoji #plain white cat