Every fed has more or less the exact same wording… something like top of the leg at the hip joint must drop below the top part of the knee. This is the same regardless of wraps, sleeves, raw, single ply, multi ply etc. The image below is taken straight from the USPA rule book.
Clearly in the image, the hip is well below the top of the knee. However, controversy always pops up when a lifter is right around this parallel point. Obviously in a meet there aren’t nice markings showing these points on the lifter, and you have about a quarter of a second to take a mental snapshot of where the lifter was at they’re lowest point, so you can see why lifts right around parallel are touch to judge. As @chris_ottawa said, different feds have different cultures of how they interpret the rules and what they want to see. My personal opinion… I’d give myself (on a good day) accuracy within 1/2 inch. So if I judge a squat that looks right a parallel, I have to ask myself if it’s possible it may have been a hair below. Because there isn’t anything that says “must CLEARLY break parallel”, just that it must break, even if it’s only a millimeter.