Index: trunk/data/validator/ignoretags.cfg
===================================================================
--- trunk/data/validator/ignoretags.cfg	(revision 9321)
+++ trunk/data/validator/ignoretags.cfg	(revision 9322)
@@ -136,4 +136,5 @@
 K:building=static_caravan
 K:leisure=recreation_ground
+K:old_railway_operator=PRR
 ;
 ; Highway Key/Value Pairs
@@ -256,2 +257,17 @@
 K:type=tmc
 K:type=TMC
+;
+; Tags not yet decided (to remove from this section when added or deprecated) 
+; see https://josm.openstreetmap.de/ticket/12240
+; see https://josm.openstreetmap.de/ticket/11915
+; see https://josm.openstreetmap.de/ticket/10991
+; see https://josm.openstreetmap.de/ticket/10759
+;
+K:golf=bunker
+K:golf=fairway
+K:maintenance=gritting
+K:man_made=mast
+K:man_made=silo
+K:power=portal
+K:route=foot
+K:seasonal=yes
Index: trunk/test/functional/org/openstreetmap/josm/data/osm/TaginfoIntegrationTest.java
===================================================================
--- trunk/test/functional/org/openstreetmap/josm/data/osm/TaginfoIntegrationTest.java	(revision 9322)
+++ trunk/test/functional/org/openstreetmap/josm/data/osm/TaginfoIntegrationTest.java	(revision 9322)
@@ -0,0 +1,85 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.data.osm;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.json.Json;
+import javax.json.JsonObject;
+import javax.json.JsonReader;
+import javax.json.JsonValue;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.openstreetmap.josm.JOSMFixture;
+import org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker;
+import org.openstreetmap.josm.data.validation.tests.TagChecker;
+import org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.ParseException;
+import org.openstreetmap.josm.gui.tagging.presets.TaggingPresets;
+import org.openstreetmap.josm.tools.HttpClient;
+import org.xml.sax.SAXException;
+
+/**
+ * Various tests with Taginfo.
+ */
+public class TaginfoIntegrationTest {
+
+    /**
+     * Setup test.
+     */
+    @BeforeClass
+    public static void setUp() {
+        JOSMFixture.createFunctionalTestFixture().init();
+    }
+
+    /**
+     * Checks that popular tags are known (i.e included in internal presets, or deprecated, or explicitely ignored)
+     * @throws SAXException if any XML parsing error occurs
+     * @throws IOException if any I/O error occurs
+     * @throws ParseException if any MapCSS parsing error occurs
+     */
+    @Test
+    public void checkPopularTags() throws SAXException, IOException, ParseException {
+        TaggingPresets.readFromPreferences();
+        new TagChecker().initialize();
+        MapCSSTagChecker mapCssTagChecker = new MapCSSTagChecker();
+        mapCssTagChecker.addMapCSS("resource://data/validator/deprecated.mapcss");
+
+        List<String> errors = new ArrayList<>();
+        try (InputStream in = HttpClient.create(new URL("https://taginfo.openstreetmap.org/api/4/tags/popular")).connect().getContent();
+             JsonReader reader = Json.createReader(in)) {
+            for (JsonValue item : reader.readObject().getJsonArray("data")) {
+                JsonObject obj = (JsonObject) item;
+                // Only consider tags with wiki pages
+                if (obj.getInt("in_wiki") == 1) {
+                    String key = obj.getString("key");
+                    String value = obj.getString("value");
+                    System.out.print("Checking "+key+"="+value+" ... ");
+                    boolean ok = true;
+                    // Check if tag is in internal presets
+                    if (!TagChecker.isTagInPresets(key, value)) {
+                        // If not, check if we have either a deprecated mapcss test for it
+                        Node n = new Node();
+                        n.put(key, value);
+                        if (mapCssTagChecker.getErrorsForPrimitive(n, false).isEmpty()) {
+                            // Or a legacy tagchecker ignore rule
+                            if (!TagChecker.isTagIgnored(key, value)) {
+                                ok = !errors.add(key +"="+ value + " - " + obj.getInt("count_all"));
+                            }
+                        }
+                    }
+                    System.out.println(ok ? "OK" : "KO");
+                }
+            }
+        }
+        for (String error : errors) {
+            System.err.println(error);
+        }
+        assertTrue(errors.toString(), errors.isEmpty());
+    }
+}