default or selected kernelversion does not have config value CONFIG_NF_NAT_MASQUERADE_IPV6.
Result is shown for kernelversion 6.9.9
CONFIG_NF_NAT_MASQUERADE_IPV6 (not configurable)
configname: CONFIG_NF_NAT_MASQUERADE_IPV6
Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>Network packet filtering framework (Netfilter)
└─>The IPv6 protocol
└─>IPv6: Netfilter Configuration
└─>NF_NAT_MASQUERADE_IPV6