Upstart is deprecated and nobody uses it anymore
Upstart was the init implementation on Ubuntu for a while, however on modern Ubuntu installations Systemd is now used
To find out if you are using Upstart, if you have a /usr/share/upstart directory that's a pretty good indicator
Jobs are the actions that Upstart performs and events are messages that are received from other processes to trigger jobs. To see a list of jobs and their configuration:
$ ls /etc/init
acpid.conf mountnfs.sh.conf
alsa-restore.conf mtab.sh.conf
alsa-state.conf networking.conf
alsa-store.conf network-interface.conf
anacron.conf network-interface-container.conf