do bumper-to-bumper warranties cover catyletic converters?
They should, but cat converters have their own federally-mandated warranties independent of the rest of the car. 8 years, 80K miles last I looked.
If you mean an “Extended Warranty, (really an insurance policy)” you will need to read the agreement. However in the US you should have, as Budd noted a year 80K coverage by the manufacturer.