handbook/cutting-edge etcupdate bootstrap

From: Edward Sanford Sutton, III <mirror176_at_hotmail.com>
Date: Sun, 23 May 2021 00:43:28 UTC
  https://docs.freebsd.org/en/books/handbook/cutting-edge section has "# etcupdate bootstrap" appearing as one of two commands to
run when switching from mergemaster. FreeBSD 12.2-STABLE r369441 did not
contain the bootstrap command, nor is it in the manual or in the manpage
but I found "Bootstrapping" section of the manpage to have "etcupdate
extract" as the command to run. Was this the intended line or am I
  I had already removed /usr/src 'before' finding I should migrate to
etcupdate from mergemaster but found I had /usr/src.svn (a backup I made
when trying to migrate to git) and the poudriere copies both matching
the currently installed system. Knowing I could use -s /path/to/source
helped me resolve that without having to shuffle a backup/redownload
into /usr/src while shuffling my updated git copy out. With
documentation I have gone over, it still feels confusing whether or not
I should have been using the -B command during this process.
Thanks again,
Edward Sutton, III