The discovery suggests that Nintendo at least toyed with the idea that the tablet system could serve as a stereoscopic display for a virtual reality headset.
Switch hackers first discovered and documented references to a "VrMode" in the Switch OS' Applet Manager services back in December when analyzing the June 2017 release of version 3.0.0 of the system's firmware.
But the community doesn't seem to have done much testing of the internal functions "IsVrModeEnabled" and "SetVrModeEnabled" at the time.
Now Switch modder OatmealDome publicly noted one of the VR functions earlier this month, rhetorically asking, "has anyone actually tried calling it?"
Fellow hacker random0666 responded with a short Twitter video showing the results of an extremely simple homebrew testing app that activates the system's VrMode functions.
The Switch's VR mode splits the screen vertically into two identical half-sized images, in much the way other VR displays split an LCD screen to create a stereoscopic 3D effect.
System-level UI elements appear on both sides of the screen when the mode is enabled, and the French text shown in the test can be roughly translated to "Please move the console away from your face and click the close button".
The location of the functions in the Switch firmware suggest they're part of Nintendo's own Switch code and not generic functions included in other Nvidia Tegra-based hardware.