As mentioned by @gmaxwell on IRC: https://botbot.me/freenode/bitcoin-core-dev/2016-12-22/?msg=78338240&page=4
A pruned wallet is a wallet that has had some transactions removed.
The is very useful for merchants who deal with very large (say 500mb+) wallets.
Possible command:
Prune Wallet: (possibly a useful command for privacy) [int: start block height] - Start Range (inclusive) [int: end block height] - End Range - (exclusive) (bool: keep unspent, default true) - If transaction has unspent output, exclude from removal. (bool: test run, default true) - Return transactions that would be removed, but don't execute. (list of txid: excluded transactions) - List of transactions that should be not removed. (bool: error if excluded txid not found, default true) - If excluded txid not found, don't continue.
