Every serious tire manufacturer collaborates with OEMs and specializes their tires to a degree, sometimes by adding acoustic foam to the inside to reduce road noise, sometimes by using a very slightly different compound, widening or narrowing the tread and sometimes even changing up the tread pattern a bit.
TireRack gives a longer, although still minimal, description of these "specialized" variants if you want to see who the OEM for each one is; Michelin typically has BMW, Porsche and Ferrari variants. The "standard" tire is the one with only the BSW (black sidewall) designation and nothing else.
Interestingly, the "standard" variant isn't always the cheapest, and this is pretty much where my knowledge ends, no idea how a customized tire can be cheaper than the stock design
