Every trust MUST name a beneficiary, but it does not need to be named in the Trust Corpus documents. In fact, it is explicitly stated that for privacy concerns, the beneficiary will be named in the Trust Minutes of the very first Trust Meeting. The Trust Minutes are private and to never be shown to the general public. Be aware, if one does not name a beneficiary and trustee(s) pass away, the Irrevocable Trust will be considered Revocable (and in some cases, not even a trust) - one does not want this to happen, so name a beneficiary as soon as possible.
NOTE: Some banks may require the beneficiary to be named in the Trust Corpus. If that is the case, one must reveal this information to have an account with this bank.