Around the beginning of September Google began rolling out Android 10 updates for Pixel smartphones. Now the smartphones Pixel 3a and Pixel 3a XL have begun to receive a new update carrying the QP1A.190711.020.C3 build number.
The update is approximately 1,188 MB in size for some users (via Android Police). Others are only seeing an update of 14 MB. The fresh Android 10 update of the Pixel 3a series delivers critical bug fixes and improvements in efficiency. To download the update, go to Settings > System > System updates.