Constant MAX_NTH_OF_BYTES 

pub const MAX_NTH_OF_BYTES: usize = _; // 1_048_576usize

The maximum size of one of S translation, a last line of defence behind MAX_NTH_OF_DEPTH: the doubling is bounded by the depth limit, but the argument it doubles is bounded only by the length of the selector, so cap the product too. Checked per nesting level, which caps the largest string ever built at roughly twice this.