OSM maps, Wikiloc and the iPhone?


Am I right in thinking that OSM maps form the basis of the offline maps used by Wikiloc for their mobile applications on iOS- and Android-based phones?

Whether this is the case or not, can anyone please tell me what the map format is for the offline Wikiloc maps on iOS-based phones?

I am also interested to know where such offline maps are stored on the iPhone.

Many thanks in advance.