clarified order of extra type variables, following names more often than occurrences;
SHELL=/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin
MAILTO=makarius
03 00 * * * $HOME/cronjob/self_update
17 00 * * * $HOME/cronjob/isabelle/Admin/cronjob/main -f > $HOME/cronjob/run/main.out 2>&1 || cat $HOME/cronjob/run/main.out