UPDATE: Galaxy S8 teardown reveals an unused OIS mechanism in the selfie camera (but not really)15
Judging by the teardown performed by JerryRigEverything on YouTube, Samsung scrapped a feature that a lot of people would have appreciated. While taking the phone apart, Zack (his real name isn't Jerry) found that the front-facing camera actually has Optical Image Stabilization hardware.
Whether this was something that Samsung wanted from its new selfie snapper, or it was just a coincidence that the chosen hardware had OIS capabilities is still unknown. But it is quite peculiar that the component itself supports OIS, yet this is not mentioned in the specs.
It is also not clear whether Samsung is planning to activate the feature with a software update at some point. In fact, depending on the way the hardware was installed, this could prove harder than pushing a firmware update with the required algorithms for the camera.