Rearchitected Object Shape (by byroot) • Instance variable management of classes/modules • Introduced just after RubyKaigi 2025, then updated w/ Namespace • Minimize memory usage around Namespace by updating memory layout (by byroot) • And others on rb_classext_t (by byroot, jhawthorn and eileencodes) • Fix SEGV on mmtk checks (by Peter Zhu) • Added Namespace#eval (by tenderlove)