You can fire the obsolescent .22 WRF in a .22 Mag This was fairly common for hunting small game when the .22 WMR was new and the .22 WRF was much more available and much less expensive.
Not much use now unless you happen on some partial boxes or are willing to pay a premium for ammo that is a trifle more powerful than .22 lr, and much less destructive than .22 WMR.