This reports the type of the address used for the local endpoint of this Phase-1 tunnel, per its description - distinct from the identity type in cisgIpsSgTunLocalType, this describes the address format (e.g., IPv4 vs IPv6) of where the tunnel actually terminates locally, regardless of what identity was used for authentication. It matters in dual-stack environments where a tunnel's authentication identity and its actual transport address type could differ, and an admin needs to know the real address family carrying the encrypted traffic. Seeing this report an IPv6 address type on a device an admin believed was still IPv4-only for VPN would be a notable and specific finding.