I have the Flight Replica's Super Cub Complete v11.
"FR_SC_Cpmplete_v11.exe" is the only file in the .zip file you buy. No readme's etc. that I know of. Unless the .exe installer itself writes readme files. I don't have anything like that on my HD FSX install.
EDIT:
There is a .PDF file with the download that doesn't seem to be saved when you quit the installer. I did save it this time but it is too large, 2048KB, to save.
(limit is 1024 for me).
Unless I'm mistaken there are two Super Cub downloads from Flight Replica's. The one I have with 18 versions of the Cub and another download that has fewer airplanes in it.