Dear Aaron, After reading https://manpages.debian.org/unstable/dpkg-dev/deb-changelog.5.en.html, it appears I used an improper syntax for "bug closing" in the debian/changelog.
I edited the the debian/changelog on salsa and pushed (https://salsa.debian.org/science-team/toulbar2). This was apparently preventing migration to testing. Should I ask you again to Finalize and sponsor it ? Kind regards Thomas