From a prospectus:
"Class R shares generally are available only to 401(k) plans, 457 plans, employer sponsored 403(b) plans, profit-sharing and money purchase pension plans, defined benefit plans and nonqualified deferred compensation plans. Class R shares also are generally available only to retirement plans where plan level or omnibus accounts are held on the books of the fund. Class R-5 shares generally are available only to retirement plans with $1 million or more in plan assets. In addition, Class R-5 shares are available for investment by American Funds Target Date Retirement Series. Class R shares generally are not available to retail nonretirement accounts, traditional and Roth Individual Retirement accounts (IRAs), Coverdell Education Savings Accounts, SEPs, SARSEPs, SIMPLE IRAs, individual 403(b) plans and 529 college savings plans."
To what base fund is RFNFX a R-5 share class? I don't recognize the core ticker characters at all.
You might check an Annual Report for the base fund, they usually have some R-class info there at the bottom of the share class tables.