text: Are your saying you did not find the tunnel?
  (https://www.openstreetmap.org/way/393494868)
  
  Or do you mean you have checked the entrances of the tunnel and observed there were no height restrictions because it can accomodate tall vehicles (4.5 meters in Belgium)?
  If that is the case, you can set maxheight=default.
  You can even make it in StreetComplete.