Jonathan Edwards, Roly Perera, Tomas Petricek: Companion Proceedings of the 9th International Conference on the Art, Science, and Engineering of Programming, Programming 2025, Prague, Czechia, June 2-6, 2025. OASIcs 134, Schloss Dagstuhl - Leibniz-Zentrum für Informatik 2025, ISBN 978-3-95977-382-9