Constant BOOTSTRAP_ZCASH_CONF 

pub const BOOTSTRAP_ZCASH_CONF: &str = "\
# zcashd-compat P2P sidecar: zcashd peers only with the local Zebra node.
# Peer selection is pinned on the zcashd command line (-connect/-listen=0);
# do not add bind=, connect=, addnode=, or listen=1 here -- these accumulate
# and cannot be overridden by the supervisor's flags.
";

Minimal config that lets zcashd start in zcashd-compat mode on first use.