[CognitiveLens]

As much as the talent behind software drove the acquisition, Sparrow also had some very solid, semi-innovative features and a sophisticated IMAP engine that are now valuable technical/IP properties for Google. I would be very surprised if they open-sourced anything from this acquisition.

[thibaut_barrere]

I don't know: from earlier researches, it seems Sparrow is based on LibEtPan which is open-source:

- http://www.etpan.org/libetpan/index.html - https://twitter.com/sparrow/status/6396505883676672

[hokkos]

The imap engine is open source : http://www.etpan.org/