Empty markup lines behavior change (maybe regression) in dev (2.21.7) than stable (2.20.0)

[K.L.]

Try engrave this ly code:

\version "2.20.0"

\header {
  title = \markup \column {
   \line { "Minuet" }
   \line { "" }
   \line { "" }
  }
  subtitle = "A study in accent and in the correct timing of half beats"
}

 

{s}

By lilypond v2.20.0:

By lilypond v2.21.7:

Sometimes a ly code converted from music sheet software (like Finale), and their composers prone to typeset casually like this. It's better to keep accordance with the original appearance.

And I noticed that in SVG results of the new version, every individual element was wrapped by a <g>, what's the design intention? Something will transform double times?