groff_man(7) on Linux
The text a239870eabd7, as Debian 8 (Jessie) shipped it.
groff `man' macros to support generation of man pages
Flags it lists
-
-rC1 -
-rD1 -
-rFT -
-rHY -
-rIN -
-rLL -
-rLT -
-rP -
-rS -
-rSN -
-rX -
-rcR