Worked on the raccoongang/edx-platform repository to resolve a bug affecting course catalog visibility, ensuring that courses with conflicting 'about' and 'none' visibility settings were properly excluded from display. Applied backend development skills using Python and Django to implement a targeted code change that corrected the filtering logic. Enhanced reliability by introducing an automated regression test, which validated the fix and safeguarded against future issues in course visibility. Maintained a clear workflow from issue identification through to automated validation, with all changes documented in a single commit, resulting in improved accuracy and user experience for course discovery within the platform.