Map:1.4.4/structure

{

   "layers": [
       {
           "id": "borders",
           "kind": "border",
           "label": "",
           "file": "2_trade-routes/borders.geojson"
       },
       {
           "id": "routes",
           "kind": "route",
           "label": "",
           "file": "2_trade-routes/routes.geojson"
       },
       {
           "id": "cities",
           "kind": "point",
           "label": "Trade town",
           "file": "2_trade-routes/cities.geojson"
       }
   ],
   "legend": [
       {
           "kind": "line",
           "swatch": "#ff0000",
           "border": "",
           "layer": "routes",
           "data": "#ff0000",
           "label": "pepper trade, 14th-15th centuries"
       },
       {
           "kind": "line",
           "swatch": "#0070ff",
           "border": "",
           "layer": "routes",
           "data": "#0070ff",
           "label": "salt trade, 16th-18th centuries"
       },
       {
           "kind": "line",
           "swatch": "#734c00",
           "border": "",
           "layer": "routes",
           "data": "#734c00",
           "label": "cattle trade, 16th-18th centuries"
       },
       {
           "kind": "line",
           "swatch": "#ffaa00",
           "border": "",
           "layer": "routes",
           "data": "#ffaa00",
           "label": "wine trade, 17th-18th centuries (from south to north)"
       },
       {
           "kind": "dot",
           "swatch": "#700000",
           "border": "",
           "layer": "cities",
           "data": "",
           "label": "trade towns"
       }
   ]

}