A preview feature is an early release of a function that is available for testing before it is declared stable. It lets vendors gather feedback, measure compatibility, and find bugs while the design and behavior may still change.
In cyber security, preview features matter because they can expose new controls or new risk. Defenders may use them to try isolation, logging, or authentication improvements earlier than a full release, but they should treat them as moving targets. Attackers also watch preview builds for weak defaults, edge-case bugs, or implementation mistakes that later become real exploits if the feature ships unchanged. In browsers, a preview feature like native Containers can help users separate accounts and session data, but it may not yet have complete hardening or documentation. The safe approach is to test it carefully, verify what is isolated, and avoid assuming preview status means production-ready security.