[Groff] What does .\" NS mean in the unstripped tmac files?

[John Gardner]

I'm digging through Groff's source, and I found this puzzling acronym
littered throughout tmac/doc-common-u:

.\" NS Dd user macro (not parsed, not callable)
.\" NS   set document date
.\" NS
.\" NS modifies:
.\" NS   doc-date-string
.\" NS   doc-command-name
.\" NS
.\" NS local variables:
.\" NS   doc-date-XXX
.\" NS
.\" NS width register `Dd' set above


My first guess was it had something to do with comment-stripping for
distributed tmac files, but that wouldn't explain why unprefixed comments
are stripped too.

The description of the .HTML-NS macro (in tmac/www.tmac.in) would suggest
something debugging-related:

.\"
.\" An auxiliary macro for HTML (without following space).
.\"
.de HTML-NS
.  nop \X^html:\\$*^\c
..