A bit late to the party, but I just tried #12653 and noticed some non-intuitive behavior (on macOS), that's probably worth explaining release notes and help.

Before this new feature I kept the entire datadir on an SSD drive, so I launch with: `bitcoind -datadir=/Volumes/SSD/Bitcoin`.

Initially I naively moved `/Volumes/SSD/Bitcoin/blocks` to `/Users/bitcoin/blocks` and added a line to `/Volumes/SSD/Bitcoin/bitcoin.conf`: `blocksdir=/Users/bitcoin/blocks`.

I then realized that I shouldn't have moved the `index` subdirectory, so I moved that back to `/Volumes/SSD/Bitcoin/blocks/index`. Having an empty `blocks` dir with just and `index` subdir is a bit weird. Perhaps after @jimpo's #11857 is merged, we could just move / assume all indexes to be there (if `-blocksdir` is set)?

Worse, it created a directory `/Users/bitcoin/blocks/blocks`, which seems like a bug. I had to set `blocksdir=/Users/bitcoin` instead.
gArgs.AddArg("-mempoolreplacement", strprintf("Enable transaction replacement in the memory pool (default: %u)", DEFAULT_ENABLE_REPLACEMENT), false, OptionsCategory::NODE_RELAY);
    gArgs.AddArg("-minrelaytxfee=<amt>", strprintf("Fees (in %s/kB) smaller than this are considered zero fee for relaying, mining and transaction creation (default: %s)",
        CURRENCY_UNIT, FormatMoney(DEFAULT_MIN_RELAY_TX_FEE)), false, OptionsCategory::NODE_RELAY);
    gArgs.AddArg("-whitelistforcerelay", strprintf("Force relay of transactions from whitelisted peers even if they violate local relay policy (default: %d)", DEFAULT_WHITELISTFORCERELAY), false, OptionsCategory::NODE_RELAY);
    gArgs.AddArg("-whitelistrelay", strprintf("Accept relayed transactions received from whitelisted peers even when not relaying transactions (default: %d)", DEFAULT_WHITELISTRELAY), false, OptionsCategory::NODE_RELAY);
    gArgs.AddArg("-blockmaxweight=<n>", strprintf("Set maximum BIP141 block weight (default: %d)", DEFAULT_BLOCK_MAX_WEIGHT), false, OptionsCategory::BLOCK_CREATION);
    gArgs.AddArg("-blockmintxfee=<amt>", strprintf("Set lowest fee rate (in %s/kB) for transactions to be included in block creation. (default: %s)", CURRENCY_UNIT, FormatMoney(DEFAULT_BLOCK_MIN_TX_FEE)), false, OptionsCategory::BLOCK_CREATION);
    gArgs.AddArg("-blockversion=<n>", "Override block version to test forking scenarios", true, OptionsCategory::BLOCK_CREATION);
    gArgs.AddArg("-rest", strprintf("Accept public REST requests (default: %u)", DEFAULT_REST_ENABLE), false, OptionsCategory::RPC);
    gArgs.AddArg("-rpcallowip=<ip>", "Allow JSON-RPC connections from specified source. Valid for <ip> are a single IP (e.g. 1.2.3.4), a network/netmask (e.g. 1.2.3.4/255.255.255.0) or a network/CIDR (e.g. 1.2.3.4/24). This option can be specified multiple times", false, OptionsCategory::RPC);
    gArgs.AddArg("-rpcauth=<userpw>", "Username and hashed password for JSON-RPC connections. The field <userpw> comes in the format: <USERNAME>:<SALT>$<HASH>. A canonical python script is included in share/rpcauth. The client then connects normally using the rpcuser=<USERNAME>/rpcpassword=<PASSWORD> pair of arguments. This option can be specified multiple times", false, OptionsCategory::RPC);
    gArgs.AddArg("-rpcbind=<addr>[:port]", "Bind to given address to listen for JSON-RPC connections. This option is ignored unless -rpcallowip is also passed. Port is optional and overrides -rpcport. Use [host]:port notation for IPv6. This option can be specified multiple times (default: 127.0.0.1 and ::1 i.e., localhost, or if -rpcallowip has been specified, 0.0.0.0 and :: i.e., all addresses)", false, OptionsCategory::RPC);
    gArgs.AddArg("-rpccookiefile=<loc>", "Location of the auth cookie. Relative paths will be prefixed by a net-specific datadir location. (default: data dir)", false, OptionsCategory::RPC);
    gArgs.AddArg("-rpcpassword=<pw>", "Password for JSON-RPC connections", false, OptionsCategory::RPC);
    gArgs.AddArg("-rpcport=<port>", strprintf("Listen for JSON-RPC connections on <port> (default: %u, testnet: %u, regtest: %u)", defaultBaseParams->RPCPort(), testnetBaseParams->RPCPort(), regtestBaseParams->RPCPort()), false, OptionsCategory::RPC);
    gArgs.AddArg("-rpcserialversion", strprintf("Sets the serialization of raw transaction or block hex returned in non-verbose mode, non-segwit(0) or segwit(1) (default: %d)", DEFAULT_RPC_SERIALIZE_VERSION), false, OptionsCategory::RPC);
    gArgs.AddArg("-rpcservertimeout=<n>", strprintf("Timeout during HTTP requests (default: %d)", DEFAULT_HTTP_SERVER_TIMEOUT), true, OptionsCategory::RPC);
    gArgs.AddArg("-rpcthreads=<n>", strprintf("Set the number of threads to service RPC calls (default: %d)", DEFAULT_HTTP_THREADS), false, OptionsCategory::RPC);
    gArgs.AddArg("-rpcuser=<user>", "Username for JSON-RPC connections", false, OptionsCategory::RPC);
    gArgs.AddArg("-rpcworkqueue=<n>", strprintf("Set the depth of the work queue to service RPC calls (default: %d)", DEFAULT_HTTP_WORKQUEUE), true, OptionsCategory::RPC);
    gArgs.AddArg("-server", "Accept command line and JSON-RPC commands", false, OptionsCategory::RPC);
#if HAVE_DECL_DAEMON
    gArgs.AddArg("-daemon", "Run in the background as a daemon and accept commands", false, OptionsCategory::OPTIONS);
#else
    hidden_args.emplace_back("-daemon");
#endif
    
    gArgs.AddHiddenArgs(hidden_args);
}
std::string LicenseInfo()