What genetics does explain concerning L3f1b1 is soley that it is of East African origin.
As for specific modern geographic locations of the L3f1b1 origin, such cannot be discerned with great accuracy, according to who populated these places in the past.
Family Tree DNA lists one woman of the San (South African) people that is L3f1b1. Which should not reflect that all of this mtDNA is of the San people of South Africa, as some Omo (of Modern Day Ethiopia) and Turkana (of Modern Day Kenya) have also produced the L3f1b1 mtDNA. As ancient and modern civilizations are not static and have always travelled/migrated for a multitude of reasons. Portugal sent "Missionaries" to East Africa during the age of European Discovery, which resulted in the common outcome of certain modern "Portugese" women having East African mtDNA (specifically that of sexual relations of those Portugese men with Ethiopian women that departed Ethiopia for Portugal). And of course; from East Africa, to Tropical Europe to the Caribbean (as peasants, overseers, laborers, colonizing opportunists, etc...) for the next navigational power, Spain. As East Africa itself played little to no role in the whole Atlantic Slave Trade (99.99% West African) with .01% being from East African (Madagascar, etc...).