Ubuntu Linux: Where is my crontab log file?

Fig.01: Ubuntu Linux: Where is my crontab log file?

Fig.01: Ubuntu Linux: Where is my crontab log file?

The default cron file is located at /var/log/syslog. To view cron related entries in this file, type:
$ sudo grep -i cron /var/log/syslog
Sample outputs:

Aug 21 06:47:01 server2 CRON[29432]: (root) CMD (test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly ))
Aug 21 07:17:01 server2 CRON[31067]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 08:17:01 server2 CRON[904]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 09:17:01 server2 CRON[2644]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 10:17:01 server2 CRON[6968]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 11:17:01 server2 CRON[9646]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 12:17:01 server2 CRON[13013]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 13:17:01 server2 CRON[14850]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 13:52:01 server2 cron[7510]: Error: bad username; while reading /etc/cron.d/backups
Aug 21 13:52:01 server2 cron[7510]: (*system*zfs-create-snapshot) ERROR (Syntax error, this crontab file will be ignored)
Aug 21 14:17:01 server2 CRON[18420]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 15:17:01 server2 CRON[21902]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 15:52:01 server2 CRON[22933]: (root) CMD (   test -x /etc/cron.daily/popularity-contest && /etc/cron.daily/popularity-contest --crond)
Aug 21 16:17:01 server2 CRON[24075]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 17:17:01 server2 CRON[25856]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 18:17:01 server2 CRON[28830]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 19:17:01 server2 CRON[30537]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 20:17:01 server2 CRON[32639]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 21:17:01 server2 CRON[1943]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 22:17:01 server2 CRON[5176]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 21 23:17:01 server2 CRON[7795]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Aug 22 00:00:01 server2 CRON[8966]: (root) CMD (invoke-rc.d atop _cron)
Aug 22 00:17:01 server2 CRON[10259]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)

Examples and usage: Ubuntu 16.04 Create a cron.log File To Log crontab Logs