Looking at the help output of listtransactions, there are sentences like:
- txid: Available for 'send' and 'receive' category of transactions.
- fee: This is negative and only available for the 'send' category of transactions.
... and some more.
I was thinking, that a boolean flag "conflicted" true/false could be the better choice than category "conflicted". I think a transaction is still category send/receive, but then conflicted=true/false.
Some opinions on this, flag vs. category would be good.