Constant SNAPPED_OPERANDS 

pub const SNAPPED_OPERANDS: &str = "operands snapped onto each other within tolerance";

The DeviationContribution::detail of a boolean whose operands were moved onto each other’s faces by a rounding residue, within the linear tolerance, before the mesh boolean cut them (#276, #291): its bound is the largest distance any operand vertex moved, so the mesh is the boolean of operands perturbed by at most that much. It travels with the boolean’s result through instances (scaled, plus the placement’s rounding, #295) and enclosing booleans, also where an enclosing boolean is measured against its exact result.