Re: [groff] 13/14: groff(1) (Synopsis, Options): Fix style nits.

[Dave Kemper]

>    * Drop notice of unsafe mode as "old" behavior; it's over 20 years old.

I wonder if "old" here was intended to contrast with AT&T troff
behavior, which was to always run in what groff considers unsafe mode
(in that it had no such distinction).

Safer mode being a groff innovation does not seem well documented
elsewhere: the Texinfo manual doesn't mention it, and groff_diff(7)
covers only input and output differences, not invocation differences.
(groff_diff(7) mentions the \n[.U] register but nothing else regarding
this mode.)  So I wonder if it's worth keeping the distinction here,
though perhaps terming it "historical" or "traditional" rather than
"old" behavior.