According to the Google Camera app code, the answer appears to be the latter. XDA reports that the code is found in version 6.3 of the app, which came with Android Q beta version 5. A line in the code reads “GCAM_SENSOR_ID_REAR_TELEPHOTO” and it happens to be a line that’s absent in Google Camera 6.2.
The code was discovered when a number of public beta users appear to have gotten Android Q beta 5 ahead of schedule. This version of the OS comes with the August 2019 security patches, indicating that it has been released at least a month too early. Considering the Google Pixel 4 only has two rear cameras, the presence of a telephoto camera may mean that it wouldn’t have a wide-angle lens. On the flip side, it indicates that it will be capable of optical zoom. (Source: XDA)