Do you mean in chats list to know how sent this last message? ie. you, your buddy or particular participant of the groupchat.

Yes, in this list. In 1-to-1 you know who sent last message but in groupchat you only see last message. It's very tiny, cosmetic detail but I realised it's quite convenient.

Captura de pantalla 2020-01-29 a las 18.17.25.png

I think it could be convenient also in 1-1 chat.

In case of 1-1 chat you already have name of your interlocutor in the header of the chat item in the list so prefixing preview with same thing doesn't seem all that useful.

In this case, I'm thinking about marking a direction instead of presenting a nickname. It could be useful, especially with ATTACHMENT.