>>> >>> I think that'd be rather confusing. For one it'd need to be >>> idle_in_transaction_timeout
Why? We're cancelling an idle transaction, not an "idle in transaction", whatever that is.
The confusion derives from the fact we are affecting a session whose state is "idle in transaction", not one that is idle. We are then, for this discussion, choosing to either kill the entire session or just the currently active transaction. After "idle_in_transaction" there is an unstated "session" being mentally placed by myself and probably others. Following that is then either "session" or "transaction" to denote what is being affected should the timeout interval come to pass.
Discarding that, probably flawed, mental model makes "idle_transaction_timeout" seem fine. "idle_in_transaction_session_timeout" would indeed be a natural complement to this.
I do not expect this concept, should it come to pass, to be that difficult to document or for someone to learn.
Along with other I still see no reason to avoid "IIT_session_timeout" at this point.