It's arguably the best STS ever made for the FD, it's discontinued and hard to come by. New this thing is like $400, used one go for around $200 if all pieces included. They make STS for the FC too, FD one is more rare so that might be the reason why you only found info on the FC one, but if you search on 7club, you'll find a few thread that talk about this shifter.
1994 MX-6 RS -- RIP 1/30/2012
1996 MX-6 M-Edition-- Sold 4/14/2019
1993 RX-7 Grand Touring
2010 Mazda3 Hatch Grand Touring