The dropbear suite provides both an ssh server and a client application (dbclient), and represents a light alternative to OpenSSH. Since it has a small footprint and uses system resources very well, it is generally used on embed devices, with limited memory and processing power (e.g routers or embed devices), where optimization is a key factor. It provides a lot features, like, for example, X11 forwarding, and it is fully compatible with the OpenSSH public key authentication.
This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-install-and-configure-dropbear-on-linux