+Two alternative methods for bar numbering can be set, especially for
+when using repeated music;
+
+@lilypond[fragment,quote,relative=1,noragged-right]
+\relative c'{
+ \set Score.alternativeNumberingStyle = #'numbers
+ \repeat volta 3 { c4 d e f | }
+ \alternative {
+ { c4 d e f | c2 d \break }
+ { f4 g a b | f4 g a b | f2 a | \break }
+ { c4 d e f | c2 d }
+ }
+ c1 \break
+ \set Score.alternativeNumberingStyle = #'numbers-with-letters
+ \repeat volta 3 { c,4 d e f | }
+ \alternative {
+ { c4 d e f | c2 d \break }
+ { f4 g a b | f4 g a b | f2 a | \break }
+ { c4 d e f | c2 d }
+ }
+ c1
+}
+@end lilypond
+
+@item
+The following is a fundamental change in LilyPond's music
+representation: Rhythmic events like @code{LyricEvent} and
+@code{NoteEvent} are no longer wrapped in @code{EventChord} unless they
+have been actually entered as part of a chord in the input. If you
+manipulate music expressions in Scheme, the new behavior may require
+changes in your code. The advantages of making input and music match
+more closely are numerous: music functions previously worked differently
+when used inside or outside of chords. Now they are the same, including
+all the possibilities of argument parsing. You can now use music
+variables inside of chords: a construct like
+@lilypond[verbatim,quote,ragged-right]
+tonic=fis'
+{ <\tonic \transpose c g \tonic> }
+@end lilypond
+@noindent
+would have been unthinkable previously. You can use
+@code{#@{@dots{}#@}} for constructing chord constituents. Music
+functions inside of chords are no longer specially treated and thus
+accept the same arguments as outside of chords. @code{\tweak} now works
+on single notes without needing to wrap them in a chord. In theory, it
+can also work on command events and lyrics now. Since that was not
+possible before, it depends on luck on a case-by-case basis whether the
+tweak internals are already receiving the necessary information. Users
+are asked to report those cases where they find @code{\tweak} not
+working according to reasonable expectations.