groff_man(7) on Linux
The text b481fca0575d, as Debian 9 (Stretch) 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