The README file included with upstart says to see the INSTALL file, but the INSTALL file isn't included. There doesn't appear to be any other documentation included with upstart about how to write new files to put into /etc/event.d. When I was using init, I had my modem configured in /etc/inittab to allow me to log in remotely. I don't anymore, and I have no idea how to configure it, because it's not documented anywhere.
INSTALL doesn't contain such documentation either. We'll have to write it.
See 'man 5 events' in the latest build.
The current man page, I feel, adequately addresses this. Reporter can reopen if there is still a documentation issue.