It is the motor for a sewage ejector pump, which is located below it in the sump.
Modern ejector pumps have the motor attached. The sewage in the tank, covers the submerged pump and motor assembly.
The fact means that it is submerged in a water based effluent, means that it can’t get hot as easily. The water is better at transferring heat than the air.
This allows a less robust motor to be used. Plus the exposed motor is lots easier to service when needed. And typically the motor is the more likely failure mode, than the pump itself going bad.
Don’t let anyone flush diaper wipes down the toilet. They wreak havoc on the system, because the pumps are not made to grind the wipes, and the clog up the pump, eventually jamming it.
The greaser could require a pumping stroke, or may be a spring loaded auto greaser. I can’t really tell from the picture.