In the note below the SVN header info, "many sections variables and can be skipped" should be "many sections and variables can be skipped".
A commit references this bug: Author: bcr Date: Fri Sep 20 12:11:38 UTC 2019 New revision: 53424 URL: https://svnweb.freebsd.org/changeset/doc/53424 Log: s/sections variables and/sections and variables/ PR: 240706 Submitted by: pauamma@gundo.com Event: EuroBSDcon 2019 Hackathon Changes: head/en_US.ISO8859-1/books/porters-handbook/order/chapter.xml
A fix was committed, thanks for reporting it.