Google has been publishing its security bulletin for the monthly Android patches for a long time, but starting October 2017 (last month), it created a special bulletin for Nexus and Pixel devices. With the newly released November patch, Google has started populating one new section in the bulletin that details "Functional updates."
Google has recently started using the monthly patches not just for security fixes, but also as an opportunity to fix functional bugs on Nexus and Pixel phones and add really urgent features that could not wait until a full system software update. So it was only a matter of time before the bulletin started mentioning these other non-security changes.
References | Category | Improvements:
A-65225835 | Audio | Volume warning threshold adjusted in some regions.
A-37943083 | Bluetooth | Improvements for Bluetooth devices only supporting AVRCP version 1.3.
A-63790458 | Bluetooth | Improved headset connection pairing.
A-64142363 | Bluetooth | Improved song info display on some Bluetooth carkits.
A-64991621 | Bluetooth | Improved metadata in some carkits.
A-65223508 | Bluetooth | Improved Bluetooth connections to some carkits.
A-65463237 | Bluetooth | Improved Magic Tether on BLE.
A-64977836 | Camera | Improved Autofocus during video capture.
A-65099590 | Camera | Improved front camera response speed.
A-64103722 | Mobile data | Adjusted YouTube switching from mobile data to Wi-Fi.
A-65113738 | Mobile data | Mobile data adjustments on 3 Network.
A-37187694 | Stability | Improved application stability.
Since these are Nexus/Pixel-specific, they won't be rolled out to other devices by default with the monthly patch level, but Google seems to have made the fixes available to OEMs as it says, "Android device manufacturers may choose to address these issues on their devices."