This is not a feature of rsync, but of your shell.

So the question "does rclone have that" doesn't make much sense, because it usually wouldn't be rclone implementing it.

For example, zsh does it here for rsync, which actually invokes `ssh` itself:

https://github.com/zsh-users/zsh/blob/3e72a52e27d8ce8d8be0ee...

https://github.com/zsh-users/zsh/blob/3e72a52e27d8ce8d8be0ee...

That said, some CLI tools come with tools for shells to help them implement such things. E.g. `mytool completion-helper ...`

But I don't get rclone SSH completions in zsh, as it doesn't call `_remote_files` for rclone:

https://github.com/zsh-users/zsh/blob/3e72a52e27d8ce8d8be0ee...