Function variable_automorphism_group 

pub fn variable_automorphism_group(
    num_vars: usize,
    clauses: &[Vec<Lit>],
    cap: usize,
) -> Option<Vec<Perm>>

The variable-permutation automorphism group of a CNF, fully enumerated via the Schreier–Sims backend (for complete symmetry breaking). None if a generator flips a phase, or |G| > cap (then the caller should use per-generator partial breaking on variable_automorphism_generators instead, which scales to arbitrarily large groups).