What opensource chats with end-to-end encryption are there at all?

Question

linux

The question was asked just for the sake of discussion and interest.
Interested in client-server chats, preferably with end-to-end encryption (End to End)
I already have experience using Jabber, I want to learn something new...

Answer 1

mIRC? There, as far as I remember, plugins for encryption on the client side are attached. Although in the current realities it is easier to use Telegram ( Secret Chats + MTProto ) to use some thread.