remove language about store implementation requirements

Author: jhamman

docs/v3/core/v3.0.rst

@@ -1258,9 +1258,7 @@ Stores
 ======
 
 A Zarr store is a system that can be used to store and retrieve data
-from a Zarr hierarchy. For a store to be compatible with this
-specification, it must support a set of operations defined in the `Abstract store
-interface`_ subsection. The store interface can be implemented using a
+from a Zarr hierarchy. The store interface can be implemented using a
 variety of underlying storage technologies, described in the
 subsection on `Store implementations`_.