&smallshare makes the screen share behave like a webcam share. ie: not larger in size vs other windows, for the publisher or the viewers. This is a push-side parameter. This is useful if a VR guests screen sharing an app of themselves, versus using a virtual camera. It can also be useful for gaming, where a larger screen share might bog down the system of the sender more than needed.
&smallshare will work on the scene-side now also, which disables the automixer's larger screen-share layout, and instead just uses an equal-sized video layout for all videos.