alt Hacker NewsWouldn't B's publication of the information make it by definition no longer a trade secret? It is now public knowledge, regardless of whether the current or former engineers might be liable for the original leak.
Any other interpretation would mean trade secrets have essentially infinite protection/NDAs apply to all of humanity.
> NDAs apply to all of humanity
The NDA doesn't apply to people who haven't signed it, but copyright law does. If you know the material you're receiving is under copyright (eg proprietary source code), and you publish work based on that copyright material, the fact that it's now widely available is not an effective defense against claims of copyright violation.
Person B in this scenario hasn't violated the NDA, but they could be sued for copyright infringement.