The team who are busy creating the Open Trasport API standard have recently spent time discussing whether there is the need to have a look-up of reference data for the standard. An example of this data would be a list of participating transport operators and their account locations (e.g. URLs).
Unlike the global banking system (which the Open Banking initiative is based upon and which is similar to what we are looking to achieve) there is no central sort-code register equivalent for every transport/transit operator.
Therefore some sort of central way to look-up even basic information seems like it is an inevitability.