+Sections and cross references:
+.Bl -column "xLix" description -offset indent -compact
+.It Li \&Sh Ta section header (excluding standard sections)
+.It Li \&Ss Ta subsection header
+.It Li \&Xr Ta cross reference to another manual page
+.It Li \&Rs Ta bibliographic reference
+.El
+.Pp
+Semantic markup for command line utilities:
+.Bl -column "xLix" description -offset indent -compact
+.It Li \&Fl Ta command line options (flags)
+.It Li \&Cm Ta command modifier
+.It Li \&Ar Ta command argument
+.It Li \&Ic Ta internal or interactive command
+.It Li \&Ev Ta environmental variable
+.It Li \&Pa Ta file system path
+.El