Hi Jan, Adding you to this lilypond-devel thread.
Short story: in 2019, Valentin moved the legacy Banter chord names code from the LilyPond source to a snippet (https://lsr.di.unimi.it/LSR/Item?id=102). This code was originally written by you, with only minor fixes from other contributors as far as I can judge from the Git history. In doing so, Valentin didn't realize that moving this code to LSR was a violation of the GPL, because the code was under GPL but LSR snippets are in the public domain.
To my knowledge, this is a more or less isolated case. It would be simpler to have all of LSR in the public domain. Would you mind sending a written statement that you release this code under the public domain?
Thanks, Jean
