During January 2026, the developer contributed to the Z3Prover/z3 repository by implementing subterm predicate support within the datatype theory, expanding the SMT solver’s ability to reason about subterm relationships. Puyral approached this by integrating subterm reflexivity and enhancing parser backtracking, which improved proof reliability and robustness. Their work involved targeted refinements across theory_datatype, datatype_decl_plugin, and datatype_rewriter components, addressing a critical segfault and strengthening backtracking logic. Using C++ and leveraging expertise in algorithm design and data structures, Puyral delivered a cohesive feature that deepened datatype reasoning capabilities and laid a solid foundation for future enhancements in SMT solver internals.