The platform code name for the fourth-generation Ford Mustang (1994–2004) was SN95.
Ford used SN95 for the major Mustang redesign introduced for the 1994 model year. It was the first substantial redesign in roughly 15 years, and production began in late 1993. The car retained a front-engine, rear-wheel-drive layout and was built on an extensively updated version of the Fox architecture, often called Fox-4.
SN95 identifies the broader fourth-generation program, which included the 1994–1998 Mustangs. Ford later refreshed the car for 1999 with its “New Edge” styling, but those vehicles are still generally grouped within the SN95 generation through 2004. This is why “New Edge” is a common mix-up: it describes the facelift and design language, not the original platform code name.
The fifth-generation Mustang followed for the 2005 model year and moved to the newer S197 platform. S550 refers to the sixth generation, while Fox is the preceding platform family rather than the fourth-generation code name.