===================================================================
RCS file: /cvs/mandoc/mandoc.1,v
retrieving revision 1.259
retrieving revision 1.264
diff -u -p -r1.259 -r1.264
--- mandoc/mandoc.1	2022/06/05 13:54:09	1.259
+++ mandoc/mandoc.1	2023/04/28 18:55:09	1.264
@@ -1,4 +1,4 @@
-.\" $Id: mandoc.1,v 1.259 2022/06/05 13:54:09 schwarze Exp $
+.\" $Id: mandoc.1,v 1.264 2023/04/28 18:55:09 schwarze Exp $
 .\"
 .\" Copyright (c) 2012, 2014-2022 Ingo Schwarze <schwarze@openbsd.org>
 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -15,7 +15,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: June 5 2022 $
+.Dd $Mdocdate: April 28 2023 $
 .Dt MANDOC 1
 .Os
 .Sh NAME
@@ -342,7 +342,6 @@ and may exceed the output width.
 Output produced by
 .Fl T Cm html
 conforms to HTML5 using optional self-closing tags.
-Default styles use only CSS1.
 Equations rendered from
 .Xr eqn 7
 blocks use MathML.
@@ -766,7 +765,7 @@ Messages displayed by
 follow this format:
 .Bd -ragged -offset indent
 .Nm :
-.Ar file : Ns Ar line : Ns Ar column : level : message : macro arguments
+.Ar file : Ns Ar line : Ns Ar column : level : message : macro argument ...
 .Pq Ar os
 .Ed
 .Pp
@@ -786,9 +785,7 @@ and
 strings are explained below.
 The name of the
 .Ar macro
-triggering the message and its
-.Ar arguments
-are omitted where meaningless.
+triggering the message and its arguments are omitted where meaningless.
 The
 .Ar os
 operating system specifier is omitted for messages that are relevant
@@ -1474,10 +1471,8 @@ A
 .Ic \&Bl ,
 .Ic \&D1 ,
 .Ic \&Dl ,
-.Ic \&MT ,
-.Ic \&RS ,
 or
-.Ic \&UR
+.Ic \&RS
 block contains nothing in its body and will produce no output.
 .It Sy "empty argument, using 0n"
 .Pq mdoc
@@ -1797,10 +1792,9 @@ it is hard to predict which tab stop position the tab 
 .Pq mdoc
 A new sentence starts in the middle of a text line.
 Start it on a new input line to help formatters produce correct spacing.
-.It Sy "invalid escape sequence"
+.It Sy "invalid escape sequence argument"
 .Pq roff
-An escape sequence has an invalid opening argument delimiter
-or the argument is of an invalid form.
+The argument of an escape sequence is of an invalid form.
 Invalid escape sequences are ignored.
 .It Sy "undefined escape, printing literally"
 .Pq roff
@@ -2314,6 +2308,18 @@ The escape sequence is ignored.
 The name given in a special character escape sequence is not known to
 .Nm .
 The escape sequence is ignored.
+.It Sy "invalid escape argument delimiter"
+.Pq roff
+An escape sequence that expects a numerical argument
+attempts to employ one of the characters
+.Qq " %&()*+-./0123456789:<=>"
+as an argument delimiter.
+The escape sequence is ignored including the invalid opening delimiter
+and the rest of the argument may appear as output text.
+While various characters can be used as argument delimiters,
+using the apostrophe-quote character
+.Pq Sq \(aq
+is recommended for readability and robustness.
 .El
 .Ss Unsupported features
 .Bl -ohang