General
Assets docs Each asset has its unique ID. By default they are private to your experience, but you can decide to make them accessible to anyone by making them public.
Packages
Packages docs You can decide to update or not instances of a package. For update details see here. A MODIFIED PACKAGE INSTANCE/COPY WONT BE UPDATED
Places
A Place is in simple terms a map/level. Each place contains all components for that portion of the experience, including its specific environment, parts, meshes, scripts, and user interface. Every place is represented by a data model.