Apart from the ubiquitous Jamfile, this directory has two subdirectories:
Yes, these names are somewhat misleading. :{
One or other directory will be included in the build according to the setting of the FILESYSTEM variable (-sFILESYSTEM=native or -sFILESYSTEM=vfs).
The alert reader will be wondering why there is no subdirectory none. That's because -sFILESYSTEM=none doesn't work ...