Modern high-energy physics (HEP) enterprises, such as the Belle II experiment (Abe et al, Belle II Technical Design Report. KEK Report 2010-1, 2010; Kou et al, The Belle II Physics book. KEK Preprint 2018-27, 2018) at the KEK laboratory in Japan, create huge amounts of data. Sophisticated algorithms for simulation, reconstruction, visualization, and analysis are required to fully exploit the
... [Show full abstract] potential of these data. We describe the core components of the Belle II software that provide the foundation for the development of complex algorithms and their efficient application on large data sets.