Ah, during the 80s and 90s, they only allocated 89.0 to 101mhz for FM radio due to previous allocations.

When users of of those bands were moved elsewhere (to mobile phones) they expanded to the standard 88.0mhz to 108mhz range in 2000. Looks like they reserved the 1mhz "guardband" of the expanded range for these unlicensed, low power stations.