List existing policies.

Returns the caller's policies, paged, each with its name, description, revision, and when it was created and last changed. Admins may list another user's policies by passing that user's username as owner, or every user's with all_users=true, which also names each policy's owner and requires ADMIN_CROSS_USER_ACCESS_ENABLED. With managed=true, returns the built-in managed policies instead. With deleted=true, returns the caller's (or owner's) deleted policies whose version history is kept, by name, each with its latest revision and when and by whom it was deleted; read a deleted policy's history with GET /api/policies/{policyName}/versions. Requires the policies:read scope.