===================================================================
RCS file: /cvs/mandoc/mandoc.1,v
retrieving revision 1.257
retrieving revision 1.263
diff -u -p -r1.257 -r1.263
--- mandoc/mandoc.1	2022/04/24 13:38:46	1.257
+++ mandoc/mandoc.1	2022/08/02 12:02:28	1.263
@@ -1,4 +1,4 @@
-.\" $Id: mandoc.1,v 1.257 2022/04/24 13:38:46 schwarze Exp $
+.\" $Id: mandoc.1,v 1.263 2022/08/02 12:02:28 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: April 24 2022 $
+.Dd $Mdocdate: August 2 2022 $
 .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.
@@ -1474,10 +1473,8 @@ 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
@@ -1754,6 +1751,15 @@ request or a
 layout modifier has an unknown
 .Ar font
 argument.
+.It Sy "ignoring distance argument"
+.Pq roff
+In addition to the margin character, an
+.Ic \&mc
+request has a second argument supposed to represent a distance, but the
+.Nm
+implementation of
+.Ic \&mc
+always ignores the second argument.
 .It Sy "odd number of characters in request"
 .Pq roff
 A
@@ -1788,23 +1794,10 @@ 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, lacks the
-closing argument delimiter, the argument is of an invalid form, or it is
-a character escape sequence with an invalid name.
-If the argument is incomplete,
-.Ic \e*
-and
-.Ic \en
-expand to an empty string,
-.Ic \eB
-to the digit
-.Sq 0 ,
-and
-.Ic \ew
-to the length of the incomplete argument.
-All other invalid escape sequences are ignored.
+The argument of an escape sequence is of an invalid form.
+Invalid escape sequences are ignored.
 .It Sy "undefined escape, printing literally"
 .Pq roff
 In an escape sequence, the first character
@@ -2124,6 +2117,13 @@ The first argument of a
 request is neither a single ASCII character
 nor a single character escape sequence.
 The request is ignored including all its arguments.
+.It Sy "skipping unusable escape sequence"
+.Pq roff
+The first argument of an
+.Ic mc
+request is neither a single ASCII character
+nor a single character escape sequence.
+All arguments are ignored and printing of a margin character is disabled.
 .It Sy "missing manual name, using \(dq\(dq"
 .Pq mdoc
 The first call to
@@ -2268,6 +2268,60 @@ or
 with invalid arguments
 .El
 The excess arguments are ignored.
+.El
+.Ss "Errors related to escape sequences"
+.Bl -ohang
+.It Sy "incomplete escape sequence"
+.Pq roff
+The end of the input line is encountered
+while parsing the argument of an escape sequence.
+In this case,
+.Ic \e*
+and
+.Ic \en
+expand to an empty string,
+.Ic \eB
+to the digit
+.Sq 0 ,
+and
+.Ic \ew
+to the length of the incomplete argument.
+All other incomplete escape sequences are ignored.
+.It Sy "invalid special character"
+.Pq roff
+A special character escape sequence is invalid,
+for example a Unicode sequence pointing to a surrogate
+or beyond the Unicode range, a \e[char...] escape sequence
+representing a control character or pointing beyond the
+.Vt unsigned char
+range, or an invalid variable-length form
+of a single-byte character escape sequence, for example writing
+.Qq \e[e]
+or
+.Qq \e[~]
+instead of
+.Qq \ee
+or
+.Qq \e~ ,
+respectively.
+The escape sequence is ignored.
+.It Sy "unknown special character"
+.Pq roff
+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