Does anyone know what the glass/indent under the side buttons is on the S22 Ultra?

[Android Central Question]

There is a oval section on the side of the phone just below the power key. I can't find any reference as to what it is or does.

 

[pags11]

5G antenna.

 

[theobject]

Future SD card expansion

 

[dov1978]

What's strange is I remember seeing it on YouTube reviews before I got mine but my S22 Ultra (Exynos) definetly doesn't have it. There must be physical differences with the body of this phone too