I work on routing and need to link GTFS stops with OSM objects. Seems like ref:STIB_MIVB is tagged extensively (in no small part thanks to you :) ) and GTFS stop IDs *should* be mostly equivalent to it, so this tag can be used for linking purposes.
According to GTFS, every day first metro 6 towards Elisabeth starts at Heysel stop 8825. It's route is distinct from regular metro 6, which starts at Roi Baudoin and passes through Heysel stop 8824. Does this information regarding stop 8825 contradict reality?