The incremental update brings the same changes that we've seen for the other carrier branded Moto X models, which is to say it adds support for Google Cloud Print to various apps; it improves battery life for a small set of users who had issues following the 4.4 update; and, it fixes an issue with Exchange email syncing. But, AT&T users are also getting another change that other models didn't. The AT&T Moto X is also getting a fix to help with international data connectivity issues when roaming.
The update has begun its rollout, so AT&T Moto X users should be seeing it hit their devices soon enough. Now, Motorola is likely going to turn its attention to bringing the 4.4.2 update to the new DROID lineup.