\relative c' {
  c1 \mark "(Center)"
  c1
  \once \override Score.RehearsalMark.self-alignment-X = #LEFT
  \mark "(Left)"
  % In 2.23.14 and later, do this instead:
  % \textMark "(Left)"
  c4 c c c
  c4 c c c
  \once \override Score.RehearsalMark.self-alignment-X = #RIGHT
  \mark "(Right)"
  % In 2.23.14 and later, do this instead:
  % \textEndMark "(Right)"
  c1
}