clarified Event_Timer.shutdown: manager thread remains until final shutdown in Session.finish;
discontinued spontaneous thread expiration from TTY age to avoid sporadic Simple_Thread.fork, which is potentially fragile in situations of resource shortage;
#!/usr/bin/env bash
set -e
FORMAT="$1"
VARIANT="$2"
"$ISABELLE_TOOL" logo
"$ISABELLE_HOME/src/Doc/prepare_document" "$FORMAT"