Aligning marks with various notation objects

If specified, text marks may be aligned with notation objects other than bar lines. These objects include ambitus, breathing-sign, clef, custos, staff-bar, left-edge, key-cancellation, key-signature, and time-signature.

In such cases, text marks will be horizontally centered above the object. However this can be changed, as demonstrated on the second line of this example (in a score with multiple staves, this setting should be done for all the staves).

\version "2.24.0"

%% http://lsr.di.unimi.it/LSR/Item?id=433

\relative c' {
  e1
  
  % the RehearsalMark will be centered above the Clef
  \override Score.RehearsalMark.break-align-symbols = #'(clef)
  \key a \major
  \clef treble
  \mark \markup { \char ##x2193 }
  e1
  
  % the RehearsalMark will be centered above the TimeSignature
  \override Score.RehearsalMark.break-align-symbols = #'(time-signature)
  \key a \major
  \clef treble
  \time 3/4
  \mark \markup { \char ##x2193 }
  e2.
  
  % the RehearsalMark will be centered above the KeySignature
  \override Score.RehearsalMark.break-align-symbols = #'(key-signature)
  \key a \major
  \clef treble
  \time 4/4
  \mark \markup { \char ##x2193 }
  e1

  \break
  e1
  
  % the RehearsalMark will be aligned with the left edge of the KeySignature
  \once \override Score.KeySignature.break-align-anchor-alignment = #LEFT
  \mark \markup { \char ##x2193 }
  \key a \major
  e1
  
  % the RehearsalMark will be aligned with the right edge of the KeySignature
  \once \override Score.KeySignature.break-align-anchor-alignment = #RIGHT
  \key a \major
  \mark \markup { \char ##x2193 }
  e1
  
  % the RehearsalMark will be aligned with the left edge of the KeySignature
  % and then shifted right by one unit.
  \once \override Score.KeySignature.break-align-anchor = #1
  \key a \major
  \mark \markup { \char ##x2193 }
  e1
}