Good afternoon.
Here you have attached a sample script that will help you achieve that(it's a python script).
This is a sample output of its execution:
laptop > python api_get_policies.py admin *** engine
Printing Delphix policies assigned to Dataset groups, dSources and vDBs...
dSource/vDB/Group, Object Reference, Policy, Policy Reference
dSources,GROUP-2,None:RefreshPolicy,POLICY_REFRESH-3
dSources,GROUP-2,Default Retention,POLICY_RETENTION-4
dSources,GROUP-2,Default Snapshot,POLICY_SNAPSHOT-6
dSources,GROUP-2,Default SnapSync,POLICY_SYNC-5
VDBS,GROUP-3,None:RefreshPolicy,POLICY_REFRESH-3
VDBS,GROUP-3,Default Retention,POLICY_RETENTION-4
VDBS,GROUP-3,Default Snapshot,POLICY_SNAPSHOT-6
VDBS,GROUP-3,Default SnapSync,POLICY_SYNC-5
DBOMSR8A1718,ORACLE_DB_CONTAINER-6,None,POLICY_RETENTION-8
DBOMSR8A1718,ORACLE_DB_CONTAINER-6,Default SnapSync,POLICY_SYNC-5
VDB1,ORACLE_DB_CONTAINER-9,None:RefreshPolicy,POLICY_REFRESH-3
VDB1,ORACLE_DB_CONTAINER-9,Default Retention,POLICY_RETENTION-4
VDB1,ORACLE_DB_CONTAINER-9,Default Snapshot,POLICY_SNAPSHOT-6
VDB2,ORACLE_DB_CONTAINER-10,None:RefreshPolicy,POLICY_REFRESH-3
VDB2,ORACLE_DB_CONTAINER-10,Default Retention,POLICY_RETENTION-4
VDB2,ORACLE_DB_CONTAINER-10,None:SnapshotPolicy,POLICY_SNAPSHOT-2
Here to be able to extract these values, you would need to first extract the group, dsources or vdb(these last 2 with the database api) references and based from that you can print out which policies are assigned to each one of them.