This refers to a technique where each item is rendered on a different layer in the page. Because of that, when moving an item to a new position it does not require 'painting' the affected area. There are some style attributes that causes the browser to create new layer for the HTML element like 'translate3d'. Tests proves that browser uses GPU for Compositing these layers which is a lot faster when the CPU does this job. explained here more briefly: https://www.chromium.org/developers/design-documents/gpu-acc...
You are right, the pages data that is fetched from the server is kept in memory for future rendering, which usually does not cause memory problems. It is up to the user how to implement search, either by searching in-memory, or change the query and reload the list.
for now yes. If you say you need it for desktop I am willing to add this support, it should be easy. to see the scrolling effect now you can simply drag or flick the list even from desktop.
Very High performance infinite list for mobile devices that besides GPU acceleration uses concepts like recycling DOM elements and minimize rendering tasks on low frame rate. All for the purpose of smooth scrolling.