When I read the chapter https://tc39.es/ecma262/#sec-data-blocks
A Shared Data Block has an identity (for the purposes of equality testing Shared Data Block values) that is address-free : it is tied not to the virtual addresses the block is mapped to in any process, but to the set of locations in memory that the block represents.
I have difficulty understanding. I do not quite understand what is meant by
set of locations in memory and how does it differ from