Constant DEFAULT_PIX_SURPLUS_SHARES 

pub const DEFAULT_PIX_SURPLUS_SHARES: u8 = hopr_protocol_pix::DEFAULT_SURPLUS_SHARES; // 16u8

Default number of shares emitted per SSA part beyond DEFAULT_PIX_SHARES_PER_POLY.

An alias for the same reason as its two siblings, and with more riding on it than they have: the surplus is part of DEFAULT_PIX_SSA_QUOTA, so a second, disagreeing default would not merely mis-describe a cycle — it would price one.