how does capistrano determine the username?

I am making my script prompt for a username, but I would like it to
offer a default of what capistrano would use. It seems as though user
and ssh_options[:username] are both nil at the point where I want to
access them. How does capistrano determine the default username? I
scoured the code for longer than I'd like to admit, and could not find
the relevant logic.

Thanks,
John

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John Joseph Bachir
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