The FreeBSD ports tree has two kinds of category. A physical category is a directory: every port lives in one. A virtual category exists only in the CATEGORIES line of a port, such as python or kde.
The physical categories are the SUBDIR entries in the top level Makefile. The virtual categories are VALID_CATEGORIES in Mk/bsd.port.mk, less the physical ones; that list first appeared in August 1999. Both are read from the ports git history and updated daily.
Every change
Newest first. A new physical category is often added to VALID_CATEGORIES a commit or two before its directory, so it can appear as a virtual category for a moment.
