Does my car have one? I can't seem to find replacement parts online
Like mentioned in above posts its part of the fuel pump ( a gaze type of mesh). usually they are 100% but if ever needed replaced the who pump has to be replaced . But up the ups side at least its one less filter to buy at service intervals . There are a few cleaners on the market and different people will have different opinions on each one but myself personally I advice people just not to let your fuel get extremely low all the time (ie don't run the car until its sucking for fuel lol!) because this is where you will suck up all the dirt at in the tank and then chances are the filter will catch it all.
I myself would only run to the "25 miles left empty" chime on the odd occasion but generally I top up when the light comes on at "50 miles to empty" I only use this as a personal guide though and I have on once or twice run the car empty but that was only to test the digital mileage to empty against the manual gauge for accuracy.
so to some it up basically just keep topped up with good fuel and fill up when the fuel tanks reaches a reasonable level but not too low. As for the cleaners well others may comment on them as I said every one as different opinions and some work and some don't I have used many brands over the years on different cars and I suppose I could say they do make a difference of some sort but one thing they do is put your mind at ease that you have tried to look after the fuel/injector system lol!
Hope this helps