For the main FreeBSD distribution:
base: /usr/src/... misc files at the top of /usr/src bin: /usr/src/bin system binaries secure: /usr/src/secure DES Sources. U.S./Canada only! etc: /usr/src/etc system files games: /usr/src/games games gnu: /usr/src/gnu sources under the GNU Public License include: /usr/src/include include files sys: /usr/src/sys kernel sources lib: /usr/src/lib libraries libexec: /usr/src/libexec more system binaries share: /usr/src/share various shared resources sbin: /usr/src/sbin even more system binaries usrbin: /usr/src/usr.bin user binaries usrsbin: /usr/src/usr.sbin that's it for the system binaries
And for the ports collection:
ports-base: /usr/ports/... misc files at the top of /usr/ports ports-editors: /usr/ports/editors text editors ports-game: /usr/ports/games games ports-lang: /usr/ports/lang programming languages ports-mail: /usr/ports/mail mail software ports-math: /usr/ports/math math software ports-net: /usr/ports/net networking software ports-news: /usr/ports/news USENET news software ports-print: /usr/ports/print printing software ports-russian: /usr/ports/russian russian software ports-shells: /usr/ports/shells various UN*X shells ports-utils: /usr/ports/utils miscellaneous utilities ports-x11: /usr/ports/x11 X11 software