This is an SSH client application.
It supports password and key authentication, agent forwarding, port forwarding, proxy jump, file transfers, and multiple sessions.
For more information, see the documentation on the SSHBorg website.
Start by creating an SSH key pair and copying the public key to the server's authorized_keys. Configure a connection host on the main page, then discover the actions in the host drop-down menu.
To do an SSH proxy jump, you need to add the public key to authorized_keys and enable agent_forwarding on every intermediate hop the SSH connection jumps through.