[monknomo]

maybe I'm showing my rural roots here, but a privy is an outhouse. Of course, it also has the "secret" meaning, but...

[tweetle_beetle]

I suspect it's making use of the 'trusted personal advisor' connotations, similar to the metaphor of having a co-pilot if you will - https://en.wikipedia.org/wiki/Privy_council

[zik]

Maybe it's referring to "code smell"?

[srikanth235]

I was thinking more in terms of something like secret or private :)