A TSB is a technical Service Bulletin. They simply provide information to the technicians regrding common problems or issues. They may also include information regarding warranty or reimbursement policy, but the mere existence of a TSB does not say anything about warranty or reimbursement for the actions discused in the TSB. One must read the specific TSB to determine this, e.g., a TSB might exist which would say 5W-20 oil can be used on earlier models which originally specified use of 5W-30 oil, or another TSB might provide additional information or a procedure to diagnose a particular problem or symptom. TSBs are simply a mechanism for the company to provide updated technical information to the mechanics/technicians in a timely and uniform manner.
P.S. Vitually all vehicles will have associated TSBs, as many general TSBs will apply to all models.