Here's a rubber gasket, sealing the area around the headphone jack—presumably for protection from water damage.

Perhaps the Alpha was intended to attain the same waterproof rating as its older brother, but something went awry?

The headphone jack's home is a blobular mess of a cable, akin to the iPhone's front-facing camera and sensor cable—with the noteworthy exception of the Alpha's front-facing camera living on its own.

On the Alpha's cable, we find the headphone jack, earpiece speaker, microphone, volume button switches, and an ambient light sensor.