-For security reasons,
-.Nm
-allows
-.Ic \&so
-file inclusion requests only with relative paths
-and only without ascending to any parent directory.
-By requesting the inclusion of a sensitive file, a malicious document
-might otherwise trick a privileged user into inadvertently displaying
-the file on the screen, revealing the file content to bystanders.
-The parser exits immediately.
-.It Sy ".so request failed"
-.Pq roff
-Servicing a
-.Ic \&so
-request requires reading an external file.
-While trying to do so, an
-.Xr open 2 ,
-.Xr stat 2 ,
-or
-.Xr read 2
-system call failed.
-The parser exits immediately.
-Before showing this message,
-.Nm
-always shows another message explaining why the system call failed.
+An input file contains a
+.Xr roff 7
+request supported by GNU troff or Heirloom troff but not by
+.Nm ,
+and it is likely that this will cause information loss
+or considerable misformatting.
+.It Sy "bad table syntax"
+.It Sy "bad table option"
+.It Sy "bad table layout"
+.It Sy "ignoring macro in table"