Tomasz Strejczek modernized date and time handling across the LadybirdBrowser/ladybird and nikitabobko/ladybird repositories by introducing a unified UnixDateTime API and refactoring legacy components for improved maintainability. He implemented a Windows MSVC demangler and overhauled time zone conversion, ensuring consistent cross-platform behavior. Using C++ and leveraging skills in API design and system programming, Tomasz replaced obsolete DateTime classes, streamlined library dependencies, and enhanced test coverage with comprehensive unit tests for edge cases like leap years. His work reduced technical debt, improved code clarity, and established a robust foundation for reliable date-time formatting and parsing throughout the codebase.