default or selected kernelversion does not have config value CONFIG_IPDDP_DECAP.
Result is shown for kernelversion 6.2.5
Appletalk-IP to IP Decapsulation support
configname: CONFIG_IPDDP_DECAP
Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>Appletalk-IP to IP Decapsulation support
In linux kernel since version 2.6.12
If you say Y here, the AppleTalk-IP code will be able to decapsulate
AppleTalk-IP frames to IP packets; this is useful if you want your
Linux box to act as an Internet gateway for an AppleTalk network.
Please see Documentation/networking/ipddp.txt for more
information. If you said Y to "AppleTalk-IP driver support" above
and you say Y here, then you cannot say Y to "IP to AppleTalk-IP
Encapsulation support", above.
AppleTalk-IP frames to IP packets; this is useful if you want your
Linux box to act as an Internet gateway for an AppleTalk network.
Please see Documentation/networking/ipddp.txt for more
information. If you said Y to "AppleTalk-IP driver support" above
and you say Y here, then you cannot say Y to "IP to AppleTalk-IP
Encapsulation support", above.