Index: trunk/src/org/openstreetmap/josm/data/validation/tests/TagChecker.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/validation/tests/TagChecker.java	(revision 17765)
+++ trunk/src/org/openstreetmap/josm/data/validation/tests/TagChecker.java	(revision 17766)
@@ -499,4 +499,5 @@
             || c == 0x0272 || c == 0x019D // "ɲ/Ɲ" (U+0272/U+019D), see #18740
             || c == 0x0273 || c == 0x019E // "ŋ/Ŋ" (U+0273/U+019E), see #18740
+            || c == 0x0142 || c == 0x0294 // see #20754
             || (key.endsWith("ref") && 0x1D2C <= c && c <= 0x1D42); // allow uppercase superscript latin characters in *ref tags
     }