In July 2025, Eike Mueller developed a flexible GTMGPC preconditioner for the firedrakeproject/firedrake repository, focusing on enhancing solver configurability for large-scale PDE problems. He implemented support for an optional restriction matrix, allowing users to fine-tune the multigrid hierarchy by specifying custom interpolation and restriction matrices. The work was carried out in Python and leveraged expertise in linear algebra, numerical methods, and scientific computing. Eike supplemented the feature with comprehensive documentation and a dedicated test case, prioritizing reliability and maintainability. Although no bugs were fixed during this period, the depth of the feature improved user control and test coverage.