Showing chords at changes

By default, every chord entered is printed. This behavior can be modified so that chord names are printed only at the start of lines or when the chord changes.

\version "2.24"

harmonies = \chordmode {
  c'1:m c:m \break
  c'1:m c:m d
}

<<
  \new ChordNames {
    \set chordChanges = ##t
    \harmonies
  }
  \new Staff {
    \harmonies
  }
>>