unused (see also 004b39bf06a5);

--- a/src/Pure/Admin/build_log.scala	Sun Nov 19 12:46:41 2023 +0100
+++ b/src/Pure/Admin/build_log.scala	Sun Nov 19 12:51:47 2023 +0100
@@ -1202,10 +1202,6 @@
     ) {
       def unknown: Boolean = !known
       def versions: (String, Option[String]) = (isabelle_version, afp_version)
-
-      def known_versions(rev: String, afp_rev: Option[String]): Boolean =
-        known && rev.nonEmpty && isabelle_version == rev &&
-        (afp_rev.isEmpty || afp_rev.get.nonEmpty && afp_version == afp_rev)
     }
 
     object Run {