back 30 years ago an RPPL was a restricted private pilot's licence.
nowadays an RPL is a recreational pilots licence.
a restricted back then was a pilot who had demonstrated competence in flight but hadn't done the cross country navigation training. he or she could do the daily inspection and could sign of the main release.
when the flying instructors perverted the legislation and introduced the GFPT you could no longer sign maintenance releases.
redrppl just read and understand the legislation. stop listening to nonsense.
the (self only) was nonsense.