Unless something has changed in recent macOS versions, by default: 1. Thunderbolt Bridge exists and is enabled. 2. All active (enabled, connected) interfaces

Unless something has changed in recent macOS versions, by default: 1. Thunderbolt Bridge exists and is enabled. 2. All active (enabled, connected) interfaces get link-local IPv6 addresses. 3. All active interfaces without static or DHCP-assigned IPv4 addresses get link-local IPv4 addresses. 3. Multicast DNS (Bonjour) is enabled. So basic networking should be automatic, though no file sharing services are enabled by default.