Just a open pit with a sump pump in it, ( been that way for 40 years) and there has not been an odor until just recently.
It pumps the water ( and it only gets water in it about 10 or so times a year, mostly from basement door going out not sealing good.
In years past, there was a sink down there to wash your hands and so, that drained into it, but it had not been used in years.
After the pump sends the water up into the pipe, it has a one way valve that does not allow the water to go back into the sump.
Also the clean out is in the same area about 5 foot above the basement floor but that is normally sealed,
Now I have not been there in several years, but trying to make sure that some repair person does not tell her 1000's of repairs that she does not need.