In the link, https://www.freebsd.org/doc/en_US.ISO8859-1/books/porters-handbook/makefile-masterdir.html There is a old example with a link that leads to no where. "japanese/xdvi300 also has all the regular patches, package files, etc. Running make there, it will take the default value for the resolution (300) and build the port normally." When I click the "japanese/xdvi300", it leads to the error "404 Not Found". Also, it seems that this example is no longer relevant so it needs to be updated with a newer example.
*** Bug 212936 has been marked as a duplicate of this bug. ***
I replaced this by examples from print/pkfonts300 and friends.
A commit references this bug: Author: mat Date: Fri Aug 4 13:42:30 UTC 2017 New revision: 50636 URL: https://svnweb.freebsd.org/changeset/doc/50636 Log: Fix the MASTERDIR/slave example with an actually existing port. PR: 212937 Reported by: zzdudcjfzz hotmail com Sponsored by: Absolight, The FreeBSD Foundation Changes: head/en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml