July 2026: Bug fix in mne-tools/mne-python to improve error message clarity by using f-strings to display actual variable values, enhancing user feedback and debugging experience. This change reduces ambiguity in error reporting and speeds issue diagnosis. Commit 7c460f3da9829b84f7e891514954f062631bdd7f (Add missing f-string prefixes to error messages (#14008)); Co-authored-by: CedricConday.

June 2026 monthly summary: Delivered targeted reliability and data integrity improvements across two repositories, reinforcing security and data processing quality for business-critical workflows. Key changes included a hardened HMAC validation path in Adyen/adyen-node-api-library to correctly handle length mismatches, with a regression test and error handling that rethrows as NexoCryptoException to prevent leaking internal errors. In mne-tools/mne-python, fixed Eyelink calibration file decoding by reading MSG lines as UTF-8, eliminating UnicodeDecodeError for non-ASCII characters. These changes reduce tampering risk, improve calibration data reliability, and extend regression coverage for future changes. Overall impact: stronger payment integration robustness, more reliable eye-tracking data processing, and clearer error semantics across code paths. Technologies/skills demonstrated: Node.js/TypeScript crypto handling and regression testing; Python UTF-8 decoding and test-driven development; cross-repo code quality and maintainability.