API First run, Python visualization, analysis tools, and command-line options.
Gui Geant4 display setup and annotations.
Geometry and Materials Detector volumes, materials, CAD imports, and reusable structures.
Optical Optical materials, Cherenkov radiation, mirrors, and photon surfaces.
Sensitivity Built-in detector responses and custom digitization plugins.
Fields Multipole magnetic fields and plugin-backed field maps.
Generator Internal particle generation and LUND input files.
Output File formats, streamer configuration, and custom output plugins.
Support Doxygen and related documentation.