zcashd is deprecated. The Z3 stack (Zebra, Zaino, Zallet) is its modular Rust replacement: a validating node, an indexing/lightwallet service and a wallet, run together. Much of the Dev Fund and ZCG spend is building toward it.
Consensus, indexing and wallet operations each have a dedicated role in the Rust successor to zcashd.
Official
zcashd deprecation & migration guide
Why zcashd is being retired and how the ecosystem moves to the Z3 stack.
Zebra
ProductionConsensus full node (zebrad): an independent Rust implementation of the Zcash protocol, replacing zcashd's consensus.
Zcash Foundation · GitHub ↗
Zaino
Feature-completeIndexing & lightwallet service: the gRPC/JSON-RPC layer that serves wallets, taking over the role lightwalletd played for zcashd.
Zingo Labs · GitHub ↗
Zallet
AlphaFull-node wallet: the daemon and RPCs that replace zcashd's built-in wallet, paired with Zebra + Zaino.
Electric Coin Co · GitHub ↗