Finding operator values from GTFS Sweden 3 static data

Hi,

We are migrating from the regional static GTFS feeds to the aggregated GTFS Sweden 3 static feed. For real-time vehicle positions, however, we still call operator-specific endpoints such as:

/gtfs-rt-sweden/sl/VehiclePositions.pb
/gtfs-rt-sweden/ul/VehiclePositions.pb
/gtfs-rt-sweden/skane/VehiclePositions.pb

The resulting vehicles are therefore associated with operator codes such as  sl ,  ul , and  skane.

In the aggregated static feed, routes are connected to agencies through  routes.txt  and  agency.txt , but I cannot find the corresponding Trafiklab operator code in the static GTFS data.

Is there an official way to map an  agency_id  from GTFS Sweden 3 to the operator code used by the GTFS-RT endpoints?

For example, is there published metadata that maps something like:

agency_id -> sl
agency_id -> ul
agency_id ->skane

Or are consumers expected to maintain an external lookup between  agency_id  values and Trafiklab’s operator codes?

It would also be useful to know whether this mapping is stable over time and whether a single operator code can correspond to multiple  agency_id  values?