Нужно для сборки FreeCAD на Qt6.
python3-module-matplotlib-3.8.4-alt1 -> sisyphus: Wed Apr 10 2024 Grigory Ustinov <grenka@altlinux> 3.8.4-alt1 - Automatically updated to 3.8.4 (Closes: #45501). - Added python3-module-matplotlib-qt6 subpackage (Closes: #49264). - Made tkAgg default backend.