AclCache removeAcl(Uuid id) {
        StandardAcl acl = this.aclsById.get(id);
        if (acl == null) {
            throw new RuntimeException("ID " + id + " not found in aclsById.");
        }
        ImmutableMap<Uuid, StandardAcl> aclsById = this.aclsById.removed(id);

        if (!this.aclsByResource.contains(acl)) {
            throw new RuntimeException("Unable to remove the ACL with ID " + id +
                    " from aclsByResource");
        }

        ImmutableNavigableSet<StandardAcl> aclsByResource = this.aclsByResource.removed(acl);
        return new AclCache(aclsByResource, aclsById);
    }
Contains all of the current ACLs indexed by UUID.
metadata/src/main/java/org/apache/kafka/metadata/authorizer/AclCache.java