Printing figured bass extender lines without a starting figure

In figured bass, the normal triads (<8 5 3> or simply <5> in LilyPond notation) are not printed at all. However, sometimes, the bass moves, while the upper voices in the chord should stay from the normal triad. The usual way for this is to print an extender line without an explicit starting figure. The way to produce such a single extender line in figured bass is to declare a bass figure as implicit, using the implicitBassFigures property of the Staff context. The most common setting would be \set Staff.implicitBassFigures = #'(5), which declares <5> an implicit figure and does not print the 5, but will print any extenders derived from it. This can be done Staff-wide (using \with as in the first staff of this example), but it can also be set/changed at any point inside the score using \set as shown in the second staff.
The problem is that one can then not have any explicit 5 figures in the score. As a workaround, one can of course declare any other number (e.g. 100) as an implicit figure and simply use this number for single extender lines.

\version "2.24.0"

%% http://lsr.di.unimi.it/LSR/Item?id=607

fb = \figuremode {
  \bassFigureExtendersOn
  s4 <5> <5> <5> |
}

music = \relative c' {
  c4 c b c |
}

\new Score { <<
    % By declaring <5> to be an implicit figure,
    % the 5 is not printed, but extenders are...
    % Staff-wide setting:
    \new Staff \with { implicitBassFigures = #'(5) } <<
      \new Voice = "FiguredBass" { \fb }
      \new Voice = "Music" { \clef "bass" \music }
    >>
    % Using \set, this can be changed anywhere inside
    % the score for only a portion of the score
    \new Staff <<
      \set Staff.implicitBassFigures = #'(5)
      \new Voice = "FiguredBass" { \fb }
      \new Voice = "Music" { \clef "bass" \music }
    >>
  >>
}