Constant DESKTOP_DISCOVERY_PORT 

pub(crate) const DESKTOP_DISCOVERY_PORT: u16 = 29700;

UDP port for desktop-to-desktop discovery. Inside the fixed block (lan_ports::LAN_PORT_RANGE, below every OS’s ephemeral range) so one firewall rule can name it. UDP and TCP port numbers are separate, so sharing a number with a TCP listener in the block is harmless.