Clear extra tags in some case, automagically match input

assets/layers/postoffices/postoffices.json

@@ -194,6 +194,26 @@
         }
       ]
     },
+    {
+      "id": "post_offic_brand",
+      "condition": "amenity=post_office",
+      "question": {
+        "en": "To which brand does this post office belong?"
+      },
+      "render": {
+        "en": "This is a {brand} post office"
+      },
+      "freeform": {
+        "type": "nsi",
+        "key": "brand",
+        "placeholder": {
+          "en": "Brand of the post office"
+        },
+        "helperArgs": [
+          "amenity=post_office"
+        ]
+      }
+    },
     {
       "id": "partner-brand",
       "render": {
@@ -639,4 +659,4 @@
       ]
     }
   ]
-}
+}

assets/layers/public_bookcase/public_bookcase.json

@@ -399,12 +399,14 @@
         "key": "brand",
         "type": "nsi",
         "helperArgs": [
-          "amenity=public_bookcase",
-          "nobrand="
+          "amenity=public_bookcase"
         ],
         "placeholder": {
           "en": "Name of the network"
-        }
+        },
+        "addExtraTags": [
+          "nobrand="
+        ]
       },
       "mappings": [
         {