replication/slot.c and replication/logical/snapbuild.c use a CRC on the
physical slot and snapshot files. It uses the same algorithm as used
e.g. for the WAL. However, they are not doing the finalization step,
FIN_CRC32() on the calculated checksums. Not that it matters much, but
it's a bit weird and inconsistent, and was probably an oversight.
- Heikki