groff_man_style(7) on Linux
The text f413298ed5cd, as Debian 13 (Trixie) shipped it.
GNU roff man page tutorial and style guide
Flags it lists
-
-dAD -
-dHF -
-dMF -
-rC1 -
-rCS -
-rCT -
-rD1 -
-rFT -
-rHY -
-rIN -
-rLL -
-rLT -
-rP -
-rS -
-rSN -
-rU1 -
-rX -
-rcR