src/Pure/PIDE/isabelle_markup.scala

   val ML_TVAR = "ML_tvar"
   val ML_NUMERAL = "ML_numeral"
   val ML_CHAR = "ML_char"
   val ML_STRING = "ML_string"
   val ML_COMMENT = "ML_comment"
-  val ML_MALFORMED = "ML_malformed"
 
   val ML_DEF = "ML_def"
   val ML_OPEN = "ML_open"
   val ML_STRUCT = "ML_struct"
   val ML_TYPING = "ML_typing"

   val STRING = "string"
   val ALTSTRING = "altstring"
   val VERBATIM = "verbatim"
   val COMMENT = "comment"
   val CONTROL = "control"
-  val MALFORMED = "malformed"
 
   val COMMAND_SPAN = "command_span"
   val IGNORED_SPAN = "ignored_span"
   val MALFORMED_SPAN = "malformed_span"