--- a/src/Pure/Tools/process_theories.scala	Sat Nov 01 00:04:57 2025 +0100
+++ b/src/Pure/Tools/process_theories.scala	Sat Nov 01 13:56:39 2025 +0100
@@ -152,7 +152,7 @@
       var unicode_symbols = false
       val dirs = new mutable.ListBuffer[Path]
       val files = new mutable.ListBuffer[Path]
-      var logic = Isabelle_System.getenv("ISABELLE_LOGIC")
+      var logic = Isabelle_System.default_logic()
       var margin = Pretty.default_margin
       var options = Options.init()
       var verbose = false