The wegcode / code de la route site keeps what we call a ‘consolidated version’ of the text, so with all the proper edits to give the current state.

In an attempt to aid you, I’ll go from the dutch version to english:

The ‘train de vehicules’ in dutch becomes ‘slepen’ and I peeked at the definitions given in the first chapters:

Which (and I’ll try and do this literally):
“each group of vehicules linked to eachother, with the aim of moving them through the same force”
So basically a vehicule + whatever it can push/pull/move (let’s assume the majority is ‘pulling’).

So the translation should equal to:

Or in short: the 100 km/h option for busses/motorcars only applies when the seats have seatbelts, speed limiter to 100 km/h, and it’s marked as a speedway, not just a 2x2 with a fysical seperation between both driving directions.