This dataset contains the GTFS file made by the public transport operator for Brussels city in Belgium:
What is a GTFS file?

The General Transit Feed Specification (GTFS), also known as GTFS static or static transit to differentiate it from the GTFS realtime extension, defines a common format for public transportation schedules and associated geographic information. GTFS "feeds" let public transit agencies publish their transit data and developers write applications that consume that data in an interoperable way.