PR #184260 missed adding _register_external_nccl_comm and the _NcclCommRegistration handle to torch/distributed/_symmetric_memory/init.py so non-ProcessGroupNCCL producers (e.g. torchcomms) can back symm_mem.rendezvous with an externally-owned ncclComm_t.
Both were underscore-prefixed and missing from all, so they weren't discoverable as public...