I was unaware of https://wiki.openstreetmap.org/wiki/NL:Key:name

However, https://api.basisregisters.vlaanderen.be/v2/straatnamen/75289 is an official API of Flemish government.

Official streetname is
  "straatnamen": [
    {
      "spelling": "H. De Coenestraat",
      "taal": "nl"
    }
  ]