Recently when I was reading the TupleTableSlot code, I noticed that the field "tts_tuple" mentioned in the comment has been removed in the higher version, but it still exists in the comment.
location:
https://github.com/postgres/postgres/blob/master/src/include/executor/tuptable.h
src/include/executor/tuptable.h:71
src/include/executor/tuptable.h:271