diff -r abd4a0f48e49 -r 28ac56e59d23 src/Pure/Admin/build_postgresql.scala
--- a/src/Pure/Admin/build_postgresql.scala	Fri Jan 20 21:52:29 2023 +0100
+++ b/src/Pure/Admin/build_postgresql.scala	Fri Jan 20 21:56:34 2023 +0100
@@ -88,7 +88,7 @@
 
     /* jar */
 
-    val jar = component_dir.path + Path.basic(download_name).ext("jar")
+    val jar = component_dir.path + Path.basic(download_name).jar
     Isabelle_System.download_file(download_url, jar, progress = progress)
   }