Blog Post
There was a slider on the quick settings window (positioned on the upper right) which let adjusting the blending between virtual home and passthrough. The blending was adjusted vertically (virtual home at top, passthrough at bottom) so I called the feature as vertical fader. It's probably not the official name of the feature. It was very cool and useful. No idea why that was removed. It doesn't make any sense to remove useful features. I wish very much that they bring it back.
I remember that. It was activating when I enabled the passthrough in home, there was a slider @ the brightness slider, so u could have bottom half passthrough and top vr etc.. Useful indeed, sad it is gone now.
Yep, that's it. It was better than space sense in some situations. I hope the team brings it back.