chatkeeper 1.3.0 accepts a top-level conversations.json, but newer ChatGPT exports split conversations across files such as conversations-000.json, conversations-001.json, and so on.
If you only care about conversations, the easiest fix is to merge those shards back into a single conversations.json and build a minimal zip containing only that file.
The script for that is:
/home/paulwright/Downloads/chats/chatkeeper-normalize-conversations.sh