GEFF: Graph Exchange File Format. - Morgan Schwartz; Caroline Malin-Mayor; Talley Lambert; Teun Huijben; Jan Funke; Laura Xénard; Mark Kittisopikul; Draga Doncila Pop; Yohsuke Fukai; Jordão Bragantini; Melisande Croft; Anniek Stokkermans; et al. (J. Open Source Softw., 2026)