Not an answer to your question but I think some forum members are trying to get matrix delisted from the recommendations because of their awful crypto practices (I seconded those members)
You send a verification requests that the other person needs to accept.
Both of you get shown the same emojis¹
If they match both of you need to say they match
You have verified it.
1: For simplicity the encryption verification UI is with emojis instead if 5*12 numbers since it is less likely to make a mistake. This is only for the UI in the background it does not use emojis for encryption.