NOTES

The NOTES file lists all the kernel options available for your version of BSD and your specific architecture. You should look at it if you're going to be building a custom kernel, to see what sorts of goodies you might like to include.

There are actually two separate NOTES files; one resides at /usr/src/sys/conf/NOTES and details all the non-platform-specific kernel options for your version of BSD, while the other resides at /usr/src/sys/(arch)/conf/NOTES and details all the platform-specific kernel options for your version of BSD and your particular architecture. "(arch)" can be i386, amd64, ia64, or (whatever you architecture happens to be).