Now that the insane week of Google app updates has passed (gotta love those Rollout Wednesdays, right?), I've had some time to dig into the APKs and have found a number of interesting things in some of them.
We'll start with Gmail, which received a fairly significant Card UI update with version 4.6.
Ads are coming to Gmail
The most significant under-the-hood and probably not active yet addition to Gmail 4.6 is ads.