Pathologic was missing because of a .git folder inside.

[yaffs-website] / web / modules / contrib / migrate_plus / migrations / migration_config_deriver.yml

id: migration_config_deriver
deriver: Drupal\migrate_plus\Plugin\MigrationConfigDeriver
# @todo: Remove if/when https://www.drupal.org/node/2797421 is fixed.
# Unused source configuration must be added to prevent errors.
source:
  plugin: embedded_data