Method isCustomProjection

src/openlayers/mapping/WebMap.js:5665–5670

(projection)

    return lang;
  }
  isCustomProjection(projection) {
    if (Util.isNumber(projection)) {
      return [-1000, -1].includes(+projection);
    }
    return ['EPSG:-1000', 'EPSG:-1'].includes(projection);
  }

  handleJSONSuffix(url) {
    if (!url.includes('.json')) {