Binary package “ssh-askpass” in ubuntu disco

under X, asks user for a passphrase for ssh-add

 This is Jim Knoble's implementation of the ssh-askpass program, originally
 called x11-ssh-askpass upstream. It is built on low-level X11 libraries,
 and therefore has minimal dependencies.
 .
 Other ssh-askpass programs are available, some of which may integrate
 better into various desktop environments.