+- edge case: decide how to deal with blk_full bad nesting, e.g.
+ .Sh .Nm .Bk .Nm .Ek .Sh found by jmc@ in ssh-keygen(1)
+ from jmc@ Wed, 14 Jul 2010 18:10:32 +0100
+
+- \\ is now implemented correctly
+ * when defining strings and macros using .ds and .de
+ * when parsing roff(7) and man(7) macro arguments
+ It does not yet work in mdoc(7) macro arguments
+ because libmdoc does not yet use mandoc_getarg().
+ Also check what happens in plain text, it must be identical to \e.
+
+- .Bd -filled should not be the same as .Bd -ragged, but align both
+ the left and right margin. In groff, it is implemented in terms
+ of .ad b, which we don't have either. Found in cksum(1).
+
+- implement blank `Bl -column', such as
+ .Bl -column
+ .It foo Ta bar
+ .El
+
+- explicitly disallow nested `Bl -column', which would clobber internal
+ flags defined for struct mdoc_macro
+
+- In .Bl -column .It, the end of the line probably has to be regarded
+ as an implicit .Ta, if there could be one, see the following mildly
+ ugly code from login.conf(5):
+ .Bl -column minpasswordlen program xetcxmotd
+ .It path Ta path Ta value of Dv _PATH_DEFPATH
+ .br
+ Default search path.
+ reported by Michal Mazurek <akfaew at jasminek dot net>
+ via jmc@ Thu, 7 Apr 2011 16:00:53 +0059
+
+- inside `.Bl -column' phrases, punctuation is handled like normal
+ text, e.g. `.Bl -column .It Fl x . Ta ...' should give "-x -."
+
+- inside `.Bl -column' phrases, TERMP_IGNDELIM handling by `Pf'
+ is not safe, e.g. `.Bl -column .It Pf a b .' gives "ab."
+ but should give "ab ."
+
+- set a meaningful default if no `Bl' list type is assigned
+
+- have a blank `It' head for `Bl -tag' not puke
+
+- prohibit `Nm' from having non-text HEAD children
+ (e.g., NetBSD mDNSShared/dns-sd.1)
+ (mdoc_html.c and mdoc_term.c `Nm' handlers can be slightly simplified)
+
+--- missing man features -----------------------------------------------
+
+- .RS/.RE can be nested, see e.g. the x11/fluxbox manuals
+ noticed by dcoppa@ Wed, Apr 13, 2011 at 04:58:14PM +0200:
+
+- groff an-ext.tmac macros (.UR, .UE) occur in xine(5)
+ reported by brad@ Sat, 15 Jan 2011 15:45:23 -0500
+
+--- missing tbl features -----------------------------------------------
+
+- implement basic non-parametric .de to support e.g. sox(1)
+ reported by naddy@ Sat, 16 Oct 2010 23:51:57 +0200
+ *** sox(1) still doesn't work, tbl(1) errors need investigation