head's /usr/src/UPDATING vs. "LOADER_DEFAULT_INTERP, documented in build(7)": not documented yet

Quoting UPDATING for head:

20180818:
        The default interpreter has been switched from 4th to Lua.
        LOADER_DEFAULT_INTERP, documented in build(7), will override the default
        interpreter.  If you have custom FORTH code you will need to set
        LOADER_DEFAULT_INTERP=4th (valid values are 4th, lua or simp) in
        src.conf for the build. . . .


But when I look at:

https://www.freebsd.org/cgi/man.cgi?query=build&apropos=0&sektion=0&manpath=FreeBSD+12-current&arch=default&format=html

or the installed build(7) for head -r338319 I do not find any
references to LOADER_DEFAULT_INTERP .

Also, from the text:

        If you have custom FORTH code you will need to set
        LOADER_DEFAULT_INTERP=4th (valid values are 4th, lua or simp) in
        src.conf for the build

I would guess that src.conf(5) should also mention LOADER_DEFAULT_INTERP
and how it should be used. But I find no references to LOADER_DEFAULT_INTERP
in:

https://www.freebsd.org/cgi/man.cgi?query=src.conf&apropos=0&sektion=0&manpath=FreeBSD+12-current&arch=default&format=html

or in what is installed for src.conf(5) for head -r338319 .

I have assumed that my long-in-use amd64 virtual-box context that I run and
update FreeBSD in (under macOS) just automatically updated sufficiently via
installkernel and installworld after building. (This assumes that all the
changes are in the freebsd-ufs partition involved and that the freebsd-boot
partition involved need not be updated.)


===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)