src/jdk.jextract/share/classes/com/sun/tools/jextract/Writer.java

@@ -39,11 +39,11 @@
     Writer(Context ctx, Map<String, byte[]> results) {
         this.log = ctx.log;
         this.results = results;
     }
 
-    static final String JEXTRACT_MANIFEST = "META-INF" + File.separatorChar + "jextract.properties";
+    static final String JEXTRACT_MANIFEST = "META-INF/jextract.properties";
 
     public boolean isEmpty() {
         return results.isEmpty();
     }