What type of rule is 'table.None' considered within ACL structures?

In Access Control List (ACL) structures within ServiceNow, the notation "table.None" specifically denotes a restrictive rule, which is crucial for managing access to data. This rule effectively means that no access is granted to the specified table, limiting what users can do with the data contained in that table.

By specifying a rule like "table.None," the intention is to prevent any read or write operations, encompassing a complete denial of access to that particular table. Hence, it serves as a safeguard to ensure that sensitive or critical data remains secure and is not inadvertently exposed to users who do not have the appropriate permissions.

This contrasts with rules that generally specify granting either read or write permissions, hence necessitating emphasis on why "table.None" aligns with the concept of a restrictive rule, ultimately ensuring data security and compliance with access control policies.