src/Pure/proof_general.ML

      ("prems-limit", 
       ("Setting for maximum number of premises printed",
        nat_option ProofContext.prems_limit)),
      ("print-depth", 
       ("Setting for the ML print depth",
-       print_depth_option))]),
+       print_depth_option)),
+     ("show-var-qmarks",
+      ("Show leading question mark of variable name",
+       bool_option show_var_qmarks))]),
    ("Tracing",
     [("trace-simplifier", 
       ("Trace simplification rules.",
        bool_option trace_simp)),
      ("trace-rules", ("Trace application of the standard rules",