A debug suspension is an immediate execution state with a non-empty execution stack. Another debug suspension is created when a named object (verb, adverb, or conjunction) is invoked in a debug suspension and it too suspends.

Four new verbs are provided. See the dictionary.

The result of 13!:13 is extended to have a column 8, which contains a * if the stack level begins a suspension, and a blank otherwise. In the display produced by 13!:1 and in the result produced by 13!:18 , a line begins with a * if the stack level begins a suspension (other lines begin with a | ).