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@codechefmarc thanks for your contribution.
I need to fix autotests first, but your MR will be reviewed and merged asap.

Quick update: I've rebased the MR with 2.0.x to re-run fixed tests. As expected no problem with this minor update, however, I would like to check if that possible to rewrite the piece of code using a better approach.

In case of failure, I will merge this MR as it is.

Related issue from core: https://www.drupal.org/project/drupal/issues/3522629 ✨ Provide access to protected properties in ConfigureSectionForm through getter methods Active