Comment 1 for bug 337456

Others include sftp, git and darcs.

sftp wants a "Subsystem sftp <path>" in the remote sshd configuration, but it can also just execute the "sftp-server" program remotely.

Git wants "git-upload-pack" on the remote for clone/fetch/etc. and "git-receive-pack" on the remote for push. Darcs needs "darcs" remotely, at least for push (and doesn't seem to provide a way to handle the case where it isn't in PATH!). For pull, I suspect darcs may use the scp protocol but am having trouble finding it in the manual.

Mercurial doesn't seem to support the short form, but does require "hg" on the remote.

So it seems that "bzr+ssh://" would be a reasonable default default, as most programs that support such a short form seem to expect themselves (or at least significant portions of themselves) to be installed remotely.