Freshness comes from each project's own release history on GitHub, checked every six hours. A recent release is not an audit; it only tells you someone is still shipping.
zcashd is archived. Its GitHub repository is read-only, and Zallet describes itself as an RPC wallet designed to replace the deprecated zcashd. Zebra is the maintained full node. If you still run zcashd, it is time to plan the move.
The wallet is also renamed where the project renamed it: Zashi is now Zodl, per its own repositories.
Active means a release in the last 90 days, Slowing within a year, Stale beyond that. Projects without tagged releases are dated by their last code change.