snippet fails with 2.23.

[Thomas Morley]

Hi,

the new doc-tagged LSR-snippet 'tambourine-example.ly'
https://lsr.di.unimi.it/LSR/Item?id=1070

%%%%%%
\paper { tagline = ##f }

#(define mydrums '((tambourine default #t 0)))

\new DrumStaff \with { instrumentName = #"Tambourine" }

\drummode {
  \set DrumStaff.drumStyleTable = #(alist->hash-table mydrums)
  \override Staff.StaffSymbol.line-positions = #'( 0 )
  \override Staff.BarLine.bar-extent = #'(-1.5 . 1.5)

  \time 6/8
  tamb8. 16 8 8 8 8 |
  tamb4. 8 8 8 |
  % the trick with the scaled duration and the shorter rest
  % is neccessary for the correct ending of the trill-span!
  tamb2.*5/6 \startTrillSpan s8 \stopTrillSpan |
}
%%%%

works fine with 2.22. but fails with master even after a run of
convert-ly, returning:

fatal error: unrecognised percussion sign: "#t"

  tamb8. 16 8 8 8 8 |

I don't get what's wrong.
Hints?

Thanks,
  Harm