Note
I installed some communications program on my Mac Plus a while ago and at every boot I'd get this extension showing up and a new "Communications Folder" in my System Folder even if I deleted it before rebooting. \
It drove me nuts and I couldn't figure out what exactly was causing it or how to remove it. I eventually just restored my System Folder from a backup.
I recently installed MS Works 3 and it installed some modem stuff and this stupid extension returned, taunting me every boot. \
Turns out it's Apple's Communications Toolbox and the only way to remove it is to find its installer, copy it to a boot disk, reboot to it, run it, hold down Option, and the Install button will change to Remove.