To set ACL on sys views sys views got materialized paths. Besides storing path info sys view record in SchemeShard contains type of sys view (what implementation has to be chosen).
Now KQP choose the implementation based on name of the sys view in .sys folder.
For materialized sys view path have to choose the implementation based on the enum value.

To support that:

• Fill table metadata for materialized sys view paths
• During resolving table name make additional navigate request to SchemeCache to receive a sys view type
• Save the sys view type in stage info
• Fill KQP task metadata proto with sys view type
• Choose sys view implementation based on sys view type when it's available
• Make an extra request to SchemeCache from SysView scan actor for materialized sys views to get domain/subdomain PathId