Thats because namespace is used as a bitmask in DirXML-EntitlementRef.
The "namespace" (or integer) portion of the DirXML-EntitlementRef attribute is used as a bitmask to hold a set of flags. Bit 0 of the 32-bit integer is used for this flag value and is known as the state bit. 0 means revoked, 1 means granted. Bit 1 is used to flag a granted entitlement that is the result of the upgrade process and is known as the upgrade bit. 1 means that the entitlement was previously granted in the legacy format and is therefore not a change in the entitlement state. Bits 2-31 are reserved for future use.