During February 2025, Daniel Naber enhanced the False Friend Rule Validation in the languagetool-org/languagetool repository, focusing on backend development and rule engine reliability using Java. He introduced an inTestMode flag that restricts tie-breaking checks to testing environments, thereby safeguarding production stability. Daniel addressed multiple edge cases related to issues #11189 and #11194, refining the validation logic to reduce false positives and improve language matching accuracy. His work included updating tests and validation mechanisms, demonstrating a methodical approach to isolating experimental logic from production. This targeted bug fix reflects a deep understanding of robust testing and backend rule management.