[groff] 02/02: Detail provenance of 'v' condition better.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit c04b58ef46f3737ae3067ac59fda3a7ce7e57856
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Mon Jul 27 07:56:31 2020 +1000

    Detail provenance of 'v' condition better.
    
    I found some more information about this.  It's the sort of thing that
    Kernighan's "ditroff" changes made unnecessary (though doubtless Ossanna
    troff continued to live in the wild for many years thanks to AT&T
    licensing fees).
---
 doc/groff.texi       |  6 ++++--
 man/groff_diff.7.man | 11 ++++++++---
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/doc/groff.texi b/doc/groff.texi
index 586bc9a..74bf0fb 100644
--- a/doc/groff.texi
+++ b/doc/groff.texi
@@ -10856,8 +10856,10 @@ True if the document is being processed in troff mode 
(i.e., the
 
 @item v
 Always false.  This condition is for compatibility with certain other
-@code{troff} implementations only (identifying a processing mode
-destined for a Versatec electrostatic plotter as the output device).
+@code{troff} implementations only.@footnote{This refers to
+@code{vtroff}, a translator that would convert the C/A/T output from
+early-vintage AT&T @code{troff} to a form suitable for Versatec and
+Benson-Varian plotters.}
 
 @item '@var{xxx}'@var{yyy}'
 True if the output produced by @var{xxx} is equal to the output produced
diff --git a/man/groff_diff.7.man b/man/groff_diff.7.man
index af07a66..69486ba 100644
--- a/man/groff_diff.7.man
+++ b/man/groff_diff.7.man
@@ -367,9 +367,14 @@ Always false.
 .
 This condition is for compatibility with certain other
 .I troff
-implementations only
-(identifying a processing mode destined for a Versatec electrostatic
-plotter as the output device).
+implementations only.
+.
+(This refers to
+.IR vtroff ,
+a translator that would convert the C/A/T output from early-vintage
+.RI AT&T\~ troff
+to a form suitable for Versatec and Benson-Varian plotters.)
+
 .
 .
 .\" ====================================================================