src/Pure/PIDE/session.scala

 
 
   /* tuning parameters */
 
   def output_delay: Time = Time.seconds(0.1)  // prover output (markup, common messages)
-  def prune_delay: Time = Time.seconds(60.0)  // prune history -- delete old versions
+  def prune_delay: Time = Time.seconds(60.0)  // prune history (delete old versions)
   def prune_size: Int = 0  // size of retained history
   def syslog_limit: Int = 100
   def reparse_limit: Int = 0