Components are continuously exercised by the mctest/mcviewtest regression suite (see the User Manual, section ??), which compiles and runs the example instrument library and compares results across platforms, CPU vs. GPU, and McStas versions using mcplotdiff-html. Some components additionally underwent dedicated, published validation against analytical models and/or measurements; velocity selectors and Fermi choppers were treated as black boxes and their line shapes cross-checked against analytical functions, and Guide/Guide_gravity trajectories were checked (with and without gravity) against analytically-computed reflection positions, directions and losses. Source_gen was cross-checked against an independent source module for a 3-Maxwellian moderator model, in wavelength/divergence line shape and absolute flux.