Why does the [ RA5 ] of rna.rtp not contain any Phosphorus atoms?

GROMACS version: 2022
GROMACS modification: No
asking for AMBER force fields.

Hi,
I guess the directive [ RA5 ] in the force field database describes an adenine residue in terminal 5’ position (something label also as 5’HO).
Alessandra

Thank you, Alessandra.
Chandraniv