logicalSurface property is a
ConstrainDOMString describing the requested or mandatory constraints placed upon the value of the
logicalSurface constrainable property.
This is used to specify whether or not
getDisplayMedia() should allow the user to choose display surfaces which are not necessarily fully visible on the screen, such as occluded windows or the complete content of windows which are large enough to require scrolling to see their entire contents.
If needed, you can determine whether or not this constraint is supported by checking the value of
MediaTrackSupportedConstraints.logicalSurface as returned by a call to
MediaDevices.getSupportedConstraints(). However, typically this is unnecessary since browsers will ignore any constraints they're unfamiliar with.