Empty staff paper: How to remove the left-hand line?

[James Harkins]

I had done this once before, but lost the file :-\

I would like to generate empty staff paper, for pencil sketching. Removing time 
signature, clefs, barlines, handling spacing -- easy.

But there is still the left-hand vertical line binding the system together. I 
cannot for the life of me find what this line is called, to remove it.

\version "2.22.1"
\language "english"

\paper {
  indent = 0.0\mm
  top-margin = 10\mm
}

\header {
  tagline = #f
}

\score {
  <<
    \new Staff { s1*22 }  % 22 is found empirically
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
    \new Staff { s1*22 }
  >>
  \layout {
    \context {
      \Staff
      \omit TimeSignature
      \omit BarLine
      \omit Clef
      \override VerticalAxisGroup
        .default-staff-staff-spacing
        .basic-distance = #10
    }
  }
}

I'm sure this is an easy question, but I haven't found the right search term 
for it -- TIA!

hjh